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+6 -6
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@@ -6,13 +6,13 @@
<span class=kt>int</span><span class=w> </span><span class=nf>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{{</span><span class=s>&quot;key&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;value&quot;</span><span class=p>}};</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>v</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;missing&quot;</span><span class=p>];</span>
<span class=w> </span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{{</span><span class=s>"key"</span><span class=p>,</span><span class=w> </span><span class=s>"value"</span><span class=p>}};</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>v</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"missing"</span><span class=p>];</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code>Assertion failed: (m_value.object-&gt;find(key) != m_value.object-&gt;end()), function operator[], file json.hpp, line 2144.
</code></pre></div> </details> <details class=example> <summary>Example 2: user-defined behavior</summary> <p>The assertion reporting can be changed by defining <code>JSON_ASSERT(x)</code> differently.</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;cstdio&gt;</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;cstdlib&gt;</span>
<span class=cp>#define JSON_ASSERT(x) if(!(x)){fprintf(stderr, &quot;assertion error in %s\n&quot;, __FUNCTION__); std::abort();}</span>
<span class=cp>#define JSON_ASSERT(x) if(!(x)){fprintf(stderr, "assertion error in %s\n", __FUNCTION__); std::abort();}</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
@@ -20,8 +20,8 @@
<span class=kt>int</span><span class=w> </span><span class=nf>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{{</span><span class=s>&quot;key&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;value&quot;</span><span class=p>}};</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>v</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;missing&quot;</span><span class=p>];</span>
<span class=w> </span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{{</span><span class=s>"key"</span><span class=p>,</span><span class=w> </span><span class=s>"value"</span><span class=p>}};</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>v</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"missing"</span><span class=p>];</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code>assertion error in operator[]
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../features/assertions/ >Runtime Assertions</a> - overview documentation</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.9.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../features/assertions/ >Runtime Assertions</a> - overview documentation</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.9.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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<!doctype html><html lang=en class=no-js> <head><meta charset=utf-8><meta name=viewport content="width=device-width,initial-scale=1"><meta name=author content="Niels Lohmann"><link href="https://json.nlohmann.me/api/macros/json_brace_init_copy_semantics/" rel="canonical"><link href=../json_assert/ rel=prev><link href=../json_throw_user/ rel=next><link rel=icon href=../../../assets/images/favicon.png><meta name=generator content="mkdocs-1.6.1, mkdocs-material-9.7.7"><title>JSON_BRACE_INIT_COPY_SEMANTICS - JSON for Modern C++</title><link rel=stylesheet href=../../../assets/stylesheets/main.ec1eaa64.min.css><link rel=stylesheet href=../../../assets/stylesheets/palette.ab4e12ef.min.css><link rel="stylesheet" href="../../../assets/external/fonts.googleapis.com/css.61a430c9.css"><style>:root{--md-text-font:"Roboto";--md-code-font:"JetBrains Mono"}</style><link rel=stylesheet href=../../../css/custom.css><script>__md_scope=new 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</code></pre></div> <p>When defined to <code>1</code>, single-element brace initialization of a <code>basic_json</code> value is treated as a copy/move of the element rather than wrapping it in a single-element array.</p> <h2 id=default-definition>Default definition<a class=headerlink href=#default-definition title="Permanent link">&para;</a></h2> <p>The default value is <code>0</code> (disabled — existing behavior is preserved).</p> <div class=highlight><pre><span></span><code><span class=cp>#define JSON_BRACE_INIT_COPY_SEMANTICS 0</span>
</code></pre></div> <h2 id=notes>Notes<a class=headerlink href=#notes title="Permanent link">&para;</a></h2> <div class="admonition note"> <p class=admonition-title>Background</p> <p>C++ always prefers the <code>initializer_list</code> constructor over the copy/move constructor for brace initialization. This means that code like</p> <div class=highlight><pre><span></span><code><span class=n>json</span><span class=w> </span><span class=n>obj</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{{</span><span class=s>&quot;key&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;value&quot;</span><span class=p>}};</span>
</code></pre></div> <h2 id=notes>Notes<a class=headerlink href=#notes title="Permanent link">&para;</a></h2> <div class="admonition note"> <p class=admonition-title>Background</p> <p>C++ always prefers the <code>initializer_list</code> constructor over the copy/move constructor for brace initialization. This means that code like</p> <div class=highlight><pre><span></span><code><span class=n>json</span><span class=w> </span><span class=n>obj</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{{</span><span class=s>"key"</span><span class=p>,</span><span class=w> </span><span class=s>"value"</span><span class=p>}};</span>
<span class=n>json</span><span class=w> </span><span class=n>j</span><span class=p>{</span><span class=n>obj</span><span class=p>};</span>
</code></pre></div> <p>creates a single-element <strong>array</strong> <code>[{"key":"value"}]</code> instead of a copy of <code>obj</code>. This behavior is compiler-dependent for older compilers (<abbr title="GNU Compiler Collection">GCC</abbr> wrapped, Clang did not), but starting from Clang 20, both compilers behave the same way.</p> <p>Enabling this macro opts into copy/move semantics for this case (see <a href="https://github.com/nlohmann/json/issues/5074">#5074</a>).</p> </div> <div class="admonition warning"> <p class=admonition-title>Opt-in only</p> <p>This macro must be defined <strong>before</strong> including <code>&lt;nlohmann/json.hpp&gt;</code>. Defining it after the include has no effect.</p> </div> <div class="admonition tip"> <p class=admonition-title>Workaround without the macro</p> <p>To explicitly create a single-element array without enabling this macro, use <code>json::array()</code>:</p> <div class=highlight><pre><span></span><code><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>array</span><span class=p>({</span><span class=n>obj</span><span class=p>});</span><span class=w> </span><span class=c1>// always creates [obj]</span>
</code></pre></div> </div> <h2 id=examples>Examples<a class=headerlink href=#examples title="Permanent link">&para;</a></h2> <details class=example> <summary>Default behavior (macro not defined)</summary> <p>Without the macro, single-element brace initialization wraps the value in an array:</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
@@ -9,10 +9,10 @@
<span class=kt>int</span><span class=w> </span><span class=nf>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>obj</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{{</span><span class=s>&quot;key&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;value&quot;</span><span class=p>}};</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>obj</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{{</span><span class=s>"key"</span><span class=p>,</span><span class=w> </span><span class=s>"value"</span><span class=p>}};</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=p>{</span><span class=n>obj</span><span class=p>};</span>
<span class=w> </span><span class=c1>// j is [{&quot;key&quot;:&quot;value&quot;}] -- single-element array, NOT a copy of obj</span>
<span class=w> </span><span class=c1>// j is [{"key":"value"}] -- single-element array, NOT a copy of obj</span>
<span class=p>}</span>
</code></pre></div> </details> <details class=example> <summary>Opt-in copy semantics (macro defined to 1)</summary> <p>With the macro, single-element brace initialization copies/moves the value:</p> <div class=highlight><pre><span></span><code><span class=cp>#define JSON_BRACE_INIT_COPY_SEMANTICS 1</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
@@ -21,9 +21,9 @@
<span class=kt>int</span><span class=w> </span><span class=nf>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>obj</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{{</span><span class=s>&quot;key&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;value&quot;</span><span class=p>}};</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>obj</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{{</span><span class=s>"key"</span><span class=p>,</span><span class=w> </span><span class=s>"value"</span><span class=p>}};</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=p>{</span><span class=n>obj</span><span class=p>};</span>
<span class=w> </span><span class=c1>// j is {&quot;key&quot;:&quot;value&quot;} -- copy of obj</span>
<span class=w> </span><span class=c1>// j is {"key":"value"} -- copy of obj</span>
<span class=p>}</span>
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../home/faq/#brace-initialization-yields-arrays><abbr title="Frequently Asked Questions">FAQ</abbr>: Brace initialization yields arrays</a></li> <li><a href=../../basic_json/basic_json/ ><strong>basic_json(initializer_list_t)</strong></a> - the affected constructor</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.13.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../home/faq/#brace-initialization-yields-arrays><abbr title="Frequently Asked Questions">FAQ</abbr>: Brace initialization yields arrays</a></li> <li><a href=../../basic_json/basic_json/ ><strong>basic_json(initializer_list_t)</strong></a> - the affected constructor</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.13.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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+60 -60
View File
@@ -9,63 +9,63 @@
<span class=kt>int</span><span class=w> </span><span class=nf>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>json_string</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>json_string</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span>
<span class=s> {</span>
<span class=s> &quot;address&quot;: {</span>
<span class=s> &quot;street&quot;: &quot;Fake Street&quot;,</span>
<span class=s> &quot;housenumber&quot;: 1</span>
<span class=s> "address": {</span>
<span class=s> "street": "Fake Street",</span>
<span class=s> "housenumber": 1</span>
<span class=s> }</span>
<span class=s> }</span>
<span class=s> </span><span class=dl>)</span><span class=s>&quot;</span><span class=p>;</span>
<span class=s> </span><span class=dl>)</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>parse</span><span class=p>(</span><span class=n>json_string</span><span class=p>);</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;Root diagnostic positions: </span><span class=se>\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\t</span><span class=s>start_pos: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>start_pos</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=sc>&#39;\n&#39;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\t</span><span class=s>end_pos:&quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>end_pos</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;Original string: </span><span class=se>\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;{</span><span class=se>\n</span><span class=s> </span><span class=se>\&quot;</span><span class=s>address</span><span class=se>\&quot;</span><span class=s>: {</span><span class=se>\n</span><span class=s> </span><span class=se>\&quot;</span><span class=s>street</span><span class=se>\&quot;</span><span class=s>: </span><span class=se>\&quot;</span><span class=s>Fake Street</span><span class=se>\&quot;</span><span class=s>,</span><span class=se>\n</span><span class=s> </span><span class=se>\&quot;</span><span class=s>housenumber</span><span class=se>\&quot;</span><span class=s>: 1</span><span class=se>\n</span><span class=s> }</span><span class=se>\n</span><span class=s> }&quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;Parsed string: </span><span class=se>\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>json_string</span><span class=p>.</span><span class=n>substr</span><span class=p>(</span><span class=n>j</span><span class=p>.</span><span class=n>start_pos</span><span class=p>(),</span><span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>end_pos</span><span class=p>()</span><span class=w> </span><span class=o>-</span><span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>start_pos</span><span class=p>())</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\n\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"Root diagnostic positions: </span><span class=se>\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\t</span><span class=s>start_pos: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>start_pos</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=sc>'\n'</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\t</span><span class=s>end_pos:"</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>end_pos</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"Original string: </span><span class=se>\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"{</span><span class=se>\n</span><span class=s> </span><span class=se>\"</span><span class=s>address</span><span class=se>\"</span><span class=s>: {</span><span class=se>\n</span><span class=s> </span><span class=se>\"</span><span class=s>street</span><span class=se>\"</span><span class=s>: </span><span class=se>\"</span><span class=s>Fake Street</span><span class=se>\"</span><span class=s>,</span><span class=se>\n</span><span class=s> </span><span class=se>\"</span><span class=s>housenumber</span><span class=se>\"</span><span class=s>: 1</span><span class=se>\n</span><span class=s> }</span><span class=se>\n</span><span class=s> }"</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"Parsed string: </span><span class=se>\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>json_string</span><span class=p>.</span><span class=n>substr</span><span class=p>(</span><span class=n>j</span><span class=p>.</span><span class=n>start_pos</span><span class=p>(),</span><span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>end_pos</span><span class=p>()</span><span class=w> </span><span class=o>-</span><span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>start_pos</span><span class=p>())</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\n\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;address diagnostic positions: </span><span class=se>\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\t</span><span class=s>start_pos:&quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>].</span><span class=n>start_pos</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=sc>&#39;\n&#39;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\t</span><span class=s>end_pos:&quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>].</span><span class=n>end_pos</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\n\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;Original string: </span><span class=se>\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;{ </span><span class=se>\&quot;</span><span class=s>street</span><span class=se>\&quot;</span><span class=s>: </span><span class=se>\&quot;</span><span class=s>Fake Street</span><span class=se>\&quot;</span><span class=s>,</span><span class=se>\n</span><span class=s> </span><span class=se>\&quot;</span><span class=s>housenumber</span><span class=se>\&quot;</span><span class=s>: 1</span><span class=se>\n</span><span class=s> }&quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;Parsed string: </span><span class=se>\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>json_string</span><span class=p>.</span><span class=n>substr</span><span class=p>(</span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>].</span><span class=n>start_pos</span><span class=p>(),</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>].</span><span class=n>end_pos</span><span class=p>()</span><span class=w> </span><span class=o>-</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>].</span><span class=n>start_pos</span><span class=p>())</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\n\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"address diagnostic positions: </span><span class=se>\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\t</span><span class=s>start_pos:"</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>].</span><span class=n>start_pos</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=sc>'\n'</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\t</span><span class=s>end_pos:"</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>].</span><span class=n>end_pos</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\n\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"Original string: </span><span class=se>\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"{ </span><span class=se>\"</span><span class=s>street</span><span class=se>\"</span><span class=s>: </span><span class=se>\"</span><span class=s>Fake Street</span><span class=se>\"</span><span class=s>,</span><span class=se>\n</span><span class=s> </span><span class=se>\"</span><span class=s>housenumber</span><span class=se>\"</span><span class=s>: 1</span><span class=se>\n</span><span class=s> }"</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"Parsed string: </span><span class=se>\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>json_string</span><span class=p>.</span><span class=n>substr</span><span class=p>(</span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>].</span><span class=n>start_pos</span><span class=p>(),</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>].</span><span class=n>end_pos</span><span class=p>()</span><span class=w> </span><span class=o>-</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>].</span><span class=n>start_pos</span><span class=p>())</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\n\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;street diagnostic positions: </span><span class=se>\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\t</span><span class=s>start_pos:&quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;street&quot;</span><span class=p>].</span><span class=n>start_pos</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=sc>&#39;\n&#39;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\t</span><span class=s>end_pos:&quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;street&quot;</span><span class=p>].</span><span class=n>end_pos</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\n\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;Original string: </span><span class=se>\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\&quot;</span><span class=s>Fake Street</span><span class=se>\&quot;</span><span class=s>&quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;Parsed string: </span><span class=se>\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>json_string</span><span class=p>.</span><span class=n>substr</span><span class=p>(</span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;street&quot;</span><span class=p>].</span><span class=n>start_pos</span><span class=p>(),</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;street&quot;</span><span class=p>].</span><span class=n>end_pos</span><span class=p>()</span><span class=w> </span><span class=o>-</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;street&quot;</span><span class=p>].</span><span class=n>start_pos</span><span class=p>())</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\n\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"street diagnostic positions: </span><span class=se>\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\t</span><span class=s>start_pos:"</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"street"</span><span class=p>].</span><span class=n>start_pos</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=sc>'\n'</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\t</span><span class=s>end_pos:"</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"street"</span><span class=p>].</span><span class=n>end_pos</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\n\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"Original string: </span><span class=se>\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\"</span><span class=s>Fake Street</span><span class=se>\"</span><span class=s>"</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"Parsed string: </span><span class=se>\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>json_string</span><span class=p>.</span><span class=n>substr</span><span class=p>(</span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"street"</span><span class=p>].</span><span class=n>start_pos</span><span class=p>(),</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"street"</span><span class=p>].</span><span class=n>end_pos</span><span class=p>()</span><span class=w> </span><span class=o>-</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"street"</span><span class=p>].</span><span class=n>start_pos</span><span class=p>())</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\n\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;housenumber diagnostic positions: </span><span class=se>\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\t</span><span class=s>start_pos:&quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;housenumber&quot;</span><span class=p>].</span><span class=n>start_pos</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=sc>&#39;\n&#39;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\t</span><span class=s>end_pos:&quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;housenumber&quot;</span><span class=p>].</span><span class=n>end_pos</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\n\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;Original string: </span><span class=se>\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;1&quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;Parsed string: </span><span class=se>\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>json_string</span><span class=p>.</span><span class=n>substr</span><span class=p>(</span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;housenumber&quot;</span><span class=p>].</span><span class=n>start_pos</span><span class=p>(),</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;housenumber&quot;</span><span class=p>].</span><span class=n>end_pos</span><span class=p>()</span><span class=w> </span><span class=o>-</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;housenumber&quot;</span><span class=p>].</span><span class=n>start_pos</span><span class=p>())</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;</span><span class=se>\n\n</span><span class=s>&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"housenumber diagnostic positions: </span><span class=se>\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\t</span><span class=s>start_pos:"</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"housenumber"</span><span class=p>].</span><span class=n>start_pos</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=sc>'\n'</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\t</span><span class=s>end_pos:"</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"housenumber"</span><span class=p>].</span><span class=n>end_pos</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\n\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"Original string: </span><span class=se>\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"1"</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"Parsed string: </span><span class=se>\n</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>json_string</span><span class=p>.</span><span class=n>substr</span><span class=p>(</span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"housenumber"</span><span class=p>].</span><span class=n>start_pos</span><span class=p>(),</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"housenumber"</span><span class=p>].</span><span class=n>end_pos</span><span class=p>()</span><span class=w> </span><span class=o>-</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"housenumber"</span><span class=p>].</span><span class=n>start_pos</span><span class=p>())</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"</span><span class=se>\n\n</span><span class=s>"</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code>Root diagnostic positions:
start_pos: 5
end_pos:109
Original string:
{
&quot;address&quot;: {
&quot;street&quot;: &quot;Fake Street&quot;,
&quot;housenumber&quot;: 1
"address": {
"street": "Fake Street",
"housenumber": 1
}
}
Parsed string:
{
&quot;address&quot;: {
&quot;street&quot;: &quot;Fake Street&quot;,
&quot;housenumber&quot;: 1
"address": {
"street": "Fake Street",
"housenumber": 1
}
}
@@ -74,13 +74,13 @@ address diagnostic positions:
end_pos:103
Original string:
{ &quot;street&quot;: &quot;Fake Street&quot;,
&quot;housenumber&quot;: 1
{ "street": "Fake Street",
"housenumber": 1
}
Parsed string:
{
&quot;street&quot;: &quot;Fake Street&quot;,
&quot;housenumber&quot;: 1
"street": "Fake Street",
"housenumber": 1
}
street diagnostic positions:
@@ -88,9 +88,9 @@ street diagnostic positions:
end_pos:63
Original string:
&quot;Fake Street&quot;
"Fake Street"
Parsed string:
&quot;Fake Street&quot;
"Fake Street"
housenumber diagnostic positions:
start_pos:92
@@ -111,23 +111,23 @@ Parsed string:
<span class=kt>int</span><span class=w> </span><span class=nf>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=c1>//Invalid json string - housenumber type must be int instead of string</span>
<span class=w> </span><span class=k>const</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>json_invalid_string</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span>
<span class=w> </span><span class=k>const</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>json_invalid_string</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span>
<span class=s> {</span>
<span class=s> &quot;address&quot;: {</span>
<span class=s> &quot;street&quot;: &quot;Fake Street&quot;,</span>
<span class=s> &quot;housenumber&quot;: &quot;1&quot;</span>
<span class=s> "address": {</span>
<span class=s> "street": "Fake Street",</span>
<span class=s> "housenumber": "1"</span>
<span class=s> }</span>
<span class=s> }</span>
<span class=s> </span><span class=dl>)</span><span class=s>&quot;</span><span class=p>;</span>
<span class=s> </span><span class=dl>)</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>parse</span><span class=p>(</span><span class=n>json_invalid_string</span><span class=p>);</span>
<span class=w> </span><span class=k>try</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>housenumber</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;housenumber&quot;</span><span class=p>];</span>
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>housenumber</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"housenumber"</span><span class=p>];</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>housenumber</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=w> </span><span class=k>catch</span><span class=w> </span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>exception</span><span class=o>&amp;</span><span class=w> </span><span class=n>e</span><span class=p>)</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=sc>&#39;\n&#39;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=sc>'\n'</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code>[json.exception.type_error.302] (bytes 92-95) type must be number, but is string
@@ -144,25 +144,25 @@ Parsed string:
<span class=kt>int</span><span class=w> </span><span class=nf>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=c1>//Invalid json string - housenumber type must be int instead of string</span>
<span class=w> </span><span class=k>const</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>json_invalid_string</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span>
<span class=w> </span><span class=k>const</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>json_invalid_string</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span>
<span class=s> {</span>
<span class=s> &quot;address&quot;: {</span>
<span class=s> &quot;street&quot;: &quot;Fake Street&quot;,</span>
<span class=s> &quot;housenumber&quot;: &quot;1&quot;</span>
<span class=s> "address": {</span>
<span class=s> "street": "Fake Street",</span>
<span class=s> "housenumber": "1"</span>
<span class=s> }</span>
<span class=s> }</span>
<span class=s> </span><span class=dl>)</span><span class=s>&quot;</span><span class=p>;</span>
<span class=s> </span><span class=dl>)</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>parse</span><span class=p>(</span><span class=n>json_invalid_string</span><span class=p>);</span>
<span class=w> </span><span class=k>try</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>housenumber</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;housenumber&quot;</span><span class=p>];</span>
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>housenumber</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"housenumber"</span><span class=p>];</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>housenumber</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=w> </span><span class=k>catch</span><span class=w> </span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>exception</span><span class=o>&amp;</span><span class=w> </span><span class=n>e</span><span class=p>)</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=sc>&#39;\n&#39;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=sc>'\n'</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code>[json.exception.type_error.302] (/address/housenumber) (bytes 92-95) type must be number, but is string
</code></pre></div> <div class=codehilite><pre><span></span><code>The output shows the exception with diagnostic path info and start/end positions.
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../integration/cmake/#json_diagnostic_positions><span class=twemoji><svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M11.769.066.067 23.206l12.76-10.843zm11.438 23.868L7.471 17.587 0 23.934zm.793-.198L12.298.463l1.719 19.24zM12.893 12.959l-5.025 4.298 5.62 2.248z"/></svg></span> JSON_Diagnostic_Positions</a> - CMake option to control the macro</li> <li><a href=../json_diagnostics/ >JSON_DIAGNOSTICS</a> - macro to control extended diagnostics</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.12.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../integration/cmake/#json_diagnostic_positions><span class=twemoji><svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M11.769.066.067 23.206l12.76-10.843zm11.438 23.868L7.471 17.587 0 23.934zm.793-.198L12.298.463l1.719 19.24zM12.893 12.959l-5.025 4.298 5.62 2.248z"/></svg></span> JSON_Diagnostic_Positions</a> - CMake option to control the macro</li> <li><a href=../json_diagnostics/ >JSON_DIAGNOSTICS</a> - macro to control extended diagnostics</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.12.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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+17 -17
View File
@@ -8,20 +8,20 @@
<span class=kt>int</span><span class=w> </span><span class=nf>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=p>;</span>
<span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;street&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;Fake Street&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;housenumber&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;12&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"street"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"Fake Street"</span><span class=p>;</span>
<span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"housenumber"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"12"</span><span class=p>;</span>
<span class=w> </span><span class=k>try</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>housenumber</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;housenumber&quot;</span><span class=p>];</span>
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>housenumber</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"housenumber"</span><span class=p>];</span>
<span class=w> </span><span class=p>}</span>
<span class=w> </span><span class=k>catch</span><span class=w> </span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>exception</span><span class=o>&amp;</span><span class=w> </span><span class=n>e</span><span class=p>)</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=sc>&#39;\n&#39;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=sc>'\n'</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code>[json.exception.type_error.302] type must be number, but is string
</code></pre></div> <p>This exception can be hard to debug if storing the value <code class=highlight><span class=s>&quot;12&quot;</span></code> and accessing it is further apart.</p> </details> <details class=example> <summary>Example 2: extended diagnostic messages</summary> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
</code></pre></div> <p>This exception can be hard to debug if storing the value <code class=highlight><span class=s>"12"</span></code> and accessing it is further apart.</p> </details> <details class=example> <summary>Example 2: extended diagnostic messages</summary> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
<span class=cp># define JSON_DIAGNOSTICS 1</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
@@ -31,16 +31,16 @@
<span class=kt>int</span><span class=w> </span><span class=nf>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=p>;</span>
<span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;street&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;Fake Street&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;housenumber&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;12&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"street"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"Fake Street"</span><span class=p>;</span>
<span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"housenumber"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"12"</span><span class=p>;</span>
<span class=w> </span><span class=k>try</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>housenumber</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;housenumber&quot;</span><span class=p>];</span>
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>housenumber</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"housenumber"</span><span class=p>];</span>
<span class=w> </span><span class=p>}</span>
<span class=w> </span><span class=k>catch</span><span class=w> </span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>exception</span><span class=o>&amp;</span><span class=w> </span><span class=n>e</span><span class=p>)</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=sc>&#39;\n&#39;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=sc>'\n'</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code>[json.exception.type_error.302] (/address/housenumber) type must be number, but is string
@@ -55,24 +55,24 @@
<span class=kt>int</span><span class=w> </span><span class=nf>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=c1>//Invalid json string - housenumber type must be int instead of string</span>
<span class=w> </span><span class=k>const</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>json_invalid_string</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span>
<span class=w> </span><span class=k>const</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>json_invalid_string</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span>
<span class=s> {</span>
<span class=s> &quot;address&quot;: {</span>
<span class=s> &quot;street&quot;: &quot;Fake Street&quot;,</span>
<span class=s> &quot;housenumber&quot;: &quot;1&quot;</span>
<span class=s> "address": {</span>
<span class=s> "street": "Fake Street",</span>
<span class=s> "housenumber": "1"</span>
<span class=s> }</span>
<span class=s> }</span>
<span class=s> </span><span class=dl>)</span><span class=s>&quot;</span><span class=p>;</span>
<span class=s> </span><span class=dl>)</span><span class=s>"</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>parse</span><span class=p>(</span><span class=n>json_invalid_string</span><span class=p>);</span>
<span class=w> </span><span class=k>try</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>housenumber</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>][</span><span class=s>&quot;housenumber&quot;</span><span class=p>];</span>
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>housenumber</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j</span><span class=p>[</span><span class=s>"address"</span><span class=p>][</span><span class=s>"housenumber"</span><span class=p>];</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>housenumber</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=w> </span><span class=k>catch</span><span class=w> </span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>exception</span><span class=o>&amp;</span><span class=w> </span><span class=n>e</span><span class=p>)</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=sc>&#39;\n&#39;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=sc>'\n'</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <p><div class=highlight><pre><span></span><code>[json.exception.type_error.302] (bytes 92-95) type must be number, but is string
</code></pre></div> The output shows the exception with start/end positions only.</p> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../integration/cmake/#json_diagnostics><span class=twemoji><svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M11.769.066.067 23.206l12.76-10.843zm11.438 23.868L7.471 17.587 0 23.934zm.793-.198L12.298.463l1.719 19.24zM12.893 12.959l-5.025 4.298 5.62 2.248z"/></svg></span> JSON_Diagnostics</a> - CMake option to control the macro</li> <li><a href=../json_diagnostic_positions/ >JSON_DIAGNOSTIC_POSITIONS</a> - macro to access positions of elements</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.10.0.</li> <li>As of version 3.11.0, the definition is allowed to vary between translation units.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> The output shows the exception with start/end positions only.</p> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../integration/cmake/#json_diagnostics><span class=twemoji><svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M11.769.066.067 23.206l12.76-10.843zm11.438 23.868L7.471 17.587 0 23.934zm.793-.198L12.298.463l1.719 19.24zM12.893 12.959l-5.025 4.298 5.62 2.248z"/></svg></span> JSON_Diagnostics</a> - CMake option to control the macro</li> <li><a href=../json_diagnostic_positions/ >JSON_DIAGNOSTIC_POSITIONS</a> - macro to access positions of elements</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.10.0.</li> <li>As of version 3.11.0, the definition is allowed to vary between translation units.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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@@ -32,8 +32,8 @@
<span class=n>NLOHMANN_JSON_SERIALIZE_ENUM</span><span class=p>(</span><span class=n>Choice</span><span class=p>,</span>
<span class=p>{</span>
<span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Choice</span><span class=o>::</span><span class=n>first</span><span class=p>,</span><span class=w> </span><span class=s>&quot;first&quot;</span><span class=w> </span><span class=p>},</span>
<span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Choice</span><span class=o>::</span><span class=n>second</span><span class=p>,</span><span class=w> </span><span class=s>&quot;second&quot;</span><span class=w> </span><span class=p>},</span>
<span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Choice</span><span class=o>::</span><span class=n>first</span><span class=p>,</span><span class=w> </span><span class=s>"first"</span><span class=w> </span><span class=p>},</span>
<span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Choice</span><span class=o>::</span><span class=n>second</span><span class=p>,</span><span class=w> </span><span class=s>"second"</span><span class=w> </span><span class=p>},</span>
<span class=p>})</span>
<span class=kt>int</span><span class=w> </span><span class=n>main</span><span class=p>()</span>
@@ -58,11 +58,11 @@
<span class=kt>void</span><span class=w> </span><span class=nf>from_json</span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=o>&amp;</span><span class=w> </span><span class=n>j</span><span class=p>,</span><span class=w> </span><span class=n>Choice</span><span class=o>&amp;</span><span class=w> </span><span class=n>ch</span><span class=p>)</span>
<span class=p>{</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>value</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=k>if</span><span class=w> </span><span class=p>(</span><span class=n>value</span><span class=w> </span><span class=o>==</span><span class=w> </span><span class=s>&quot;first&quot;</span><span class=p>)</span>
<span class=w> </span><span class=k>if</span><span class=w> </span><span class=p>(</span><span class=n>value</span><span class=w> </span><span class=o>==</span><span class=w> </span><span class=s>"first"</span><span class=p>)</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=n>ch</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>Choice</span><span class=o>::</span><span class=n>first</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=w> </span><span class=k>else</span><span class=w> </span><span class=k>if</span><span class=w> </span><span class=p>(</span><span class=n>value</span><span class=w> </span><span class=o>==</span><span class=w> </span><span class=s>&quot;second&quot;</span><span class=p>)</span>
<span class=w> </span><span class=k>else</span><span class=w> </span><span class=k>if</span><span class=w> </span><span class=p>(</span><span class=n>value</span><span class=w> </span><span class=o>==</span><span class=w> </span><span class=s>"second"</span><span class=p>)</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=n>ch</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>Choice</span><span class=o>::</span><span class=n>second</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
@@ -72,11 +72,11 @@
<span class=p>{</span>
<span class=w> </span><span class=k>if</span><span class=w> </span><span class=p>(</span><span class=n>ch</span><span class=w> </span><span class=o>==</span><span class=w> </span><span class=n>Choice</span><span class=o>::</span><span class=n>first</span><span class=p>)</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;first&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"first"</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=w> </span><span class=k>else</span><span class=w> </span><span class=k>if</span><span class=w> </span><span class=p>(</span><span class=n>ch</span><span class=w> </span><span class=o>==</span><span class=w> </span><span class=n>Choice</span><span class=o>::</span><span class=n>second</span><span class=p>)</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;second&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"second"</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=p>}</span>
@@ -88,4 +88,4 @@
<span class=w> </span><span class=c1>// uses user-defined from_json function</span>
<span class=w> </span><span class=n>Choice</span><span class=w> </span><span class=n>ch</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>Choice</span><span class=o>&gt;</span><span class=p>();</span>
<span class=p>}</span>
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../integration/cmake/#json_disableenumserialization><span class=twemoji><svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M11.769.066.067 23.206l12.76-10.843zm11.438 23.868L7.471 17.587 0 23.934zm.793-.198L12.298.463l1.719 19.24zM12.893 12.959l-5.025 4.298 5.62 2.248z"/></svg></span> JSON_DisableEnumSerialization</a> - CMake option to control the macro</li> <li><a href=../nlohmann_json_serialize_enum/ ><code>NLOHMANN_JSON_SERIALIZE_ENUM</code></a> - serialize/deserialize an enum</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.11.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../integration/cmake/#json_disableenumserialization><span class=twemoji><svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M11.769.066.067 23.206l12.76-10.843zm11.438 23.868L7.471 17.587 0 23.934zm.793-.198L12.298.463l1.719 19.24zM12.893 12.959l-5.025 4.298 5.62 2.248z"/></svg></span> JSON_DisableEnumSerialization</a> - CMake option to control the macro</li> <li><a href=../nlohmann_json_serialize_enum/ ><code>NLOHMANN_JSON_SERIALIZE_ENUM</code></a> - serialize/deserialize an enum</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.11.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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+1 -1
View File
@@ -8,4 +8,4 @@
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
<span class=p>...</span>
</code></pre></div> </details> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.10.5.</li> <li>Added <code>JSON_HAS_CPP_23</code> in version 3.12.0.</li> <li>Added <code>JSON_HAS_CPP_26</code> in version 3.13.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.10.5.</li> <li>Added <code>JSON_HAS_CPP_23</code> in version 3.12.0.</li> <li>Added <code>JSON_HAS_CPP_26</code> in version 3.13.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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+1 -1
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@@ -4,4 +4,4 @@
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
<span class=p>...</span>
</code></pre></div> </details> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.10.5.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.10.5.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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+1 -1
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@@ -3,4 +3,4 @@
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
<span class=p>...</span>
</code></pre></div> </details> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.11.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.11.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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+1 -1
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@@ -3,4 +3,4 @@
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
<span class=p>...</span>
</code></pre></div> </details> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.11.3.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.11.3.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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+1 -1
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@@ -3,4 +3,4 @@
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
<span class=p>...</span>
</code></pre></div> </details> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.13.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.13.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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@@ -3,4 +3,4 @@
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
<span class=p>...</span>
</code></pre></div> </details> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.11.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.11.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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+1 -1
View File
@@ -4,4 +4,4 @@
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
<span class=p>...</span>
</code></pre></div> </details> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.10.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.10.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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+1 -1
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@@ -4,4 +4,4 @@
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
<span class=p>...</span>
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../home/exceptions/#switch-off-exceptions>Switch off exceptions</a> for more information how to switch off exceptions</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <p>Added in version 2.1.0.</p> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../home/exceptions/#switch-off-exceptions>Switch off exceptions</a> for more information how to switch off exceptions</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <p>Added in version 2.1.0.</p> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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@@ -5,4 +5,4 @@
<span class=p>...</span>
</code></pre></div> </details> <div class="admonition example"> <p class=admonition-title>Example</p> <p>The following warning will be shown in case a different version of the library was already included:</p> <div class=highlight><pre><span></span><code>Already included a different version of the library!
</code></pre></div> </div> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <p>Added in version 3.11.0.</p> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </div> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <p>Added in version 3.11.0.</p> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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@@ -4,4 +4,4 @@
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
<span class=p>...</span>
</code></pre></div> </details> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <p>Added in version 3.2.0.</p> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <p>Added in version 3.2.0.</p> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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+3 -3
View File
@@ -15,10 +15,10 @@
<span class=cp>#define JSON_TRY_USER if(true)</span>
<span class=cp>#define JSON_CATCH_USER(exception) if(false)</span>
<span class=cp>#define JSON_THROW_USER(exception) \</span>
<span class=cp> {std::clog &lt;&lt; &quot;Error in &quot; &lt;&lt; __FILE__ &lt;&lt; &quot;:&quot; &lt;&lt; __LINE__ \</span>
<span class=cp> &lt;&lt; &quot; (function &quot; &lt;&lt; __FUNCTION__ &lt;&lt; &quot;) - &quot; \</span>
<span class=cp> {std::clog &lt;&lt; "Error in " &lt;&lt; __FILE__ &lt;&lt; ":" &lt;&lt; __LINE__ \</span>
<span class=cp> &lt;&lt; " (function " &lt;&lt; __FUNCTION__ &lt;&lt; ") - " \</span>
<span class=cp> &lt;&lt; (exception).what() &lt;&lt; std::endl; \</span>
<span class=cp> std::abort();}</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../home/exceptions/#switch-off-exceptions>Switch off exceptions</a> for more information how to switch off exceptions</li> <li><a href=../json_noexception/ >JSON_NOEXCEPTION</a> - switch off exceptions</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.1.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../home/exceptions/#switch-off-exceptions>Switch off exceptions</a> for more information how to switch off exceptions</li> <li><a href=../json_noexception/ >JSON_NOEXCEPTION</a> - switch off exceptions</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.1.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 2013-2026 Niels Lohmann </div> </div> <div class=md-social> <a href="https://github.com/nlohmann" target="_blank" rel="noopener" title="github.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 512 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M173.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6m-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3m44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9M252.8 8C114.1 8 8 113.3 8 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C436.2 457.8 504 362.9 504 252 504 113.3 391.5 8 252.8 8M105.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1m-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7m32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1m-11.4-14.7c-1.6 1-1.6 3.6 0 5.9s4.3 3.3 5.6 2.3c1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2"/></svg> </a> <a href="https://www.linkedin.com/in/nielslohmann/" target="_blank" rel="noopener" title="www.linkedin.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 448 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M416 32H31.9C14.3 32 0 46.5 0 64.3v383.4C0 465.5 14.3 480 31.9 480H416c17.6 0 32-14.5 32-32.3V64.3c0-17.8-14.4-32.3-32-32.3M135.4 416H69V202.2h66.5V416zM102.2 96a38.5 38.5 0 1 1 0 77 38.5 38.5 0 1 1 0-77m282.1 320h-66.4V312c0-24.8-.5-56.7-34.5-56.7-34.6 0-39.9 27-39.9 54.9V416h-66.4V202.2h63.7v29.2h.9c8.9-16.8 30.6-34.5 62.9-34.5 67.2 0 79.7 44.3 79.7 101.9z"/></svg> </a> <a href="https://www.xing.com/profile/Niels_Lohmann" target="_blank" rel="noopener" title="www.xing.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 384 512"><!-- Font Awesome FreLine truncated
+4 -4
View File
@@ -6,7 +6,7 @@
<span class=kt>int</span><span class=w> </span><span class=nf>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;42&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"42"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
@@ -18,15 +18,15 @@
<span class=kt>int</span><span class=w> </span><span class=nf>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=c1>// auto j = &quot;42&quot;_json; // This line would fail to compile,</span>
<span class=w> </span><span class=c1>// auto j = "42"_json; // This line would fail to compile,</span>
<span class=w> </span><span class=c1>// because the UDLs are not in the global namespace</span>
<span class=w> </span><span class=c1>// Bring the UDLs into scope</span>
<span class=w> </span><span class=k>using</span><span class=w> </span><span class=k>namespace</span><span class=w> </span><span class=nn>nlohmann</span><span class=o>::</span><span class=nn>json_literals</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;42&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"42"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=mi>42</span>
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../operator_literal_json/ ><code>operator""_json</code></a></li> <li><a href=../../operator_literal_json_pointer/ ><code>operator""_json_pointer</code></a></li> <li><a href=../../../integration/cmake/#json_globaludls><span class=twemoji><svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M11.769.066.067 23.206l12.76-10.843zm11.438 23.868L7.471 17.587 0 23.934zm.793-.198L12.298.463l1.719 19.24zM12.893 12.959l-5.025 4.298 5.62 2.248z"/></svg></span> JSON_GlobalUDLs</a> - CMake option to control the macro</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.11.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../operator_literal_json/ ><code>operator""_json</code></a></li> <li><a href=../../operator_literal_json_pointer/ ><code>operator""_json_pointer</code></a></li> <li><a href=../../../integration/cmake/#json_globaludls><span class=twemoji><svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M11.769.066.067 23.206l12.76-10.843zm11.438 23.868L7.471 17.587 0 23.934zm.793-.198L12.298.463l1.719 19.24zM12.893 12.959l-5.025 4.298 5.62 2.248z"/></svg></span> JSON_GlobalUDLs</a> - CMake option to control the macro</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.11.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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@@ -1,7 +1,7 @@
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</code></pre></div> <p>When defined to <code>0</code>, implicit conversions are switched off. By default, implicit conversions are switched on. The value directly affects <a href=../../basic_json/operator_ValueType/ ><code>operator ValueType</code></a>.</p> <h2 id=default-definition>Default definition<a class=headerlink href=#default-definition title="Permanent link">&para;</a></h2> <p>By default, implicit conversions are enabled.</p> <div class=highlight><pre><span></span><code><span class=cp>#define JSON_USE_IMPLICIT_CONVERSIONS 1</span>
</code></pre></div> <h2 id=notes>Notes<a class=headerlink href=#notes title="Permanent link">&para;</a></h2> <div class="admonition info"> <p class=admonition-title>Future behavior change</p> <p>Implicit conversions will be switched off by default in the next major release of the library.</p> <p>You can prepare existing code by already defining <code>JSON_USE_IMPLICIT_CONVERSIONS</code> to <code>0</code> and replace any implicit conversions with calls to <a href=../../basic_json/get/ ><code>get</code></a>.</p> </div> <div class="admonition hint"> <p class=admonition-title>CMake option</p> <p>Implicit conversions can also be controlled with the CMake option <a href=../../../integration/cmake/#json_implicitconversions><code>JSON_ImplicitConversions</code></a> (<code>ON</code> by default) which defines <code>JSON_USE_IMPLICIT_CONVERSIONS</code> accordingly.</p> </div> <h2 id=examples>Examples<a class=headerlink href=#examples title="Permanent link">&para;</a></h2> <details class=example> <summary>Example</summary> <p>This is an example for an implicit conversion:</p> <div class=highlight><pre><span></span><code><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;Hello, world!&quot;</span><span class=p>;</span>
</code></pre></div> <h2 id=notes>Notes<a class=headerlink href=#notes title="Permanent link">&para;</a></h2> <div class="admonition info"> <p class=admonition-title>Future behavior change</p> <p>Implicit conversions will be switched off by default in the next major release of the library.</p> <p>You can prepare existing code by already defining <code>JSON_USE_IMPLICIT_CONVERSIONS</code> to <code>0</code> and replace any implicit conversions with calls to <a href=../../basic_json/get/ ><code>get</code></a>.</p> </div> <div class="admonition hint"> <p class=admonition-title>CMake option</p> <p>Implicit conversions can also be controlled with the CMake option <a href=../../../integration/cmake/#json_implicitconversions><code>JSON_ImplicitConversions</code></a> (<code>ON</code> by default) which defines <code>JSON_USE_IMPLICIT_CONVERSIONS</code> accordingly.</p> </div> <h2 id=examples>Examples<a class=headerlink href=#examples title="Permanent link">&para;</a></h2> <details class=example> <summary>Example</summary> <p>This is an example for an implicit conversion:</p> <div class=highlight><pre><span></span><code><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"Hello, world!"</span><span class=p>;</span>
<span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>s</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j</span><span class=p>;</span>
</code></pre></div> <p>When <code>JSON_USE_IMPLICIT_CONVERSIONS</code> is defined to <code>0</code>, the code above does no longer compile. Instead, it must be written like this:</p> <div class=highlight><pre><span></span><code><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;Hello, world!&quot;</span><span class=p>;</span>
</code></pre></div> <p>When <code>JSON_USE_IMPLICIT_CONVERSIONS</code> is defined to <code>0</code>, the code above does no longer compile. Instead, it must be written like this:</p> <div class=highlight><pre><span></span><code><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"Hello, world!"</span><span class=p>;</span>
<span class=k>auto</span><span class=w> </span><span class=n>s</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=o>&gt;</span><span class=p>();</span>
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../basic_json/operator_ValueType/ ><strong>operator ValueType</strong></a> - get a value (implicit)</li> <li><a href=../../basic_json/get/ ><strong>get</strong></a> - get a value (explicit)</li> <li><a href=../../../integration/cmake/#json_implicitconversions><span class=twemoji><svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M11.769.066.067 23.206l12.76-10.843zm11.438 23.868L7.471 17.587 0 23.934zm.793-.198L12.298.463l1.719 19.24zM12.893 12.959l-5.025 4.298 5.62 2.248z"/></svg></span> JSON_ImplicitConversions</a> - CMake option to control the macro</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.9.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../basic_json/operator_ValueType/ ><strong>operator ValueType</strong></a> - get a value (implicit)</li> <li><a href=../../basic_json/get/ ><strong>get</strong></a> - get a value (explicit)</li> <li><a href=../../../integration/cmake/#json_implicitconversions><span class=twemoji><svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M11.769.066.067 23.206l12.76-10.843zm11.438 23.868L7.471 17.587 0 23.934zm.793-.198L12.298.463l1.719 19.24zM12.893 12.959l-5.025 4.298 5.62 2.248z"/></svg></span> JSON_ImplicitConversions</a> - CMake option to control the macro</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.9.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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@@ -4,4 +4,4 @@
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
<span class=p>...</span>
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../integration/cmake/#json_legacydiscardedvaluecomparison><span class=twemoji><svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M11.769.066.067 23.206l12.76-10.843zm11.438 23.868L7.471 17.587 0 23.934zm.793-.198L12.298.463l1.719 19.24zM12.893 12.959l-5.025 4.298 5.62 2.248z"/></svg></span> JSON_LegacyDiscardedValueComparison</a> - CMake option to control the macro</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.11.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../integration/cmake/#json_legacydiscardedvaluecomparison><span class=twemoji><svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M11.769.066.067 23.206l12.76-10.843zm11.438 23.868L7.471 17.587 0 23.934zm.793-.198L12.298.463l1.719 19.24zM12.893 12.959l-5.025 4.298 5.62 2.248z"/></svg></span> JSON_LegacyDiscardedValueComparison</a> - CMake option to control the macro</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.11.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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@@ -81,9 +81,9 @@
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>setw</span><span class=p>(</span><span class=mi>4</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>example_json</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=p>{</span>
<span class=w> </span><span class=nt>&quot;Aa&quot;</span><span class=p>:</span><span class=w> </span><span class=mf>3.142</span><span class=p>,</span>
<span class=w> </span><span class=nt>&quot;Ab&quot;</span><span class=p>:</span><span class=w> </span><span class=mf>1.777</span><span class=p>,</span>
<span class=w> </span><span class=nt>&quot;Ba&quot;</span><span class=p>:</span><span class=w> </span><span class=mi>23</span><span class=p>,</span>
<span class=w> </span><span class=nt>&quot;Bb&quot;</span><span class=p>:</span><span class=w> </span><span class=mi>42</span>
<span class=w> </span><span class=nt>"Aa"</span><span class=p>:</span><span class=w> </span><span class=mf>3.142</span><span class=p>,</span>
<span class=w> </span><span class=nt>"Ab"</span><span class=p>:</span><span class=w> </span><span class=mf>1.777</span><span class=p>,</span>
<span class=w> </span><span class=nt>"Ba"</span><span class=p>:</span><span class=w> </span><span class=mi>23</span><span class=p>,</span>
<span class=w> </span><span class=nt>"Bb"</span><span class=p>:</span><span class=w> </span><span class=mi>42</span>
<span class=p>}</span>
</code></pre></div> <p>Notes:</p> <ul> <li><code>A</code> and <code>B</code> are default-constructible. This is a requirement for using the macro.</li> <li><code>A</code> has private members and is not a derived class. Hence, macro <code>NLOHMANN_DEFINE_TYPE_INTRUSIVE</code> is used.</li> <li>As <code>B</code> is a derived class, <code>NLOHMANN_DEFINE_TYPE_INTRUSIVE</code> is not applicable, but <code>NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE</code> must be used.</li> <li>The macro <code>NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE</code> is used <em>inside</em> the class use as <code>NLOHMANN_DEFINE_TYPE_INTRUSIVE</code>.</li> </ul> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../nlohmann_define_type_intrusive/ >NLOHMANN_DEFINE_TYPE_INTRUSIVE / NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT / NLOHMANN_DEFINE_TYPE_INTRUSIVE_ONLY_SERIALIZE</a> for similar macros that can be defined <em>inside</em> a non-derived type.</li> <li><a href=../nlohmann_define_type_non_intrusive/ >NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE / NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT / NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE</a> for similar macros that can be defined <em>outside</em> a non-derived type.</li> <li><a href=../../../features/arbitrary_types/ >Arbitrary Type Conversions</a> for an overview.</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ol> <li>Added in version 3.12.0.</li> <li>Added in version 3.12.0.</li> <li>Added in version 3.12.0.</li> <li>Added in version 3.12.0.</li> <li>Added in version 3.12.0.</li> <li>Added in version 3.12.0.</li> </ol> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 2013-2026 Niels Lohmann </div> </div> <div class=md-social> <a href="https://github.com/nlohmann" target="_blank" rel="noopener" title="github.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 512 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M173.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6m-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3m44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9M252.8 8C114.1 8 8 113.3 8 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C436.2 457.8 504 362.9 504 252 504 113.3 391.5 8 252.8 8M105.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1m-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7m32.4 35.6c-Line truncated
</code></pre></div> <p>Notes:</p> <ul> <li><code>A</code> and <code>B</code> are default-constructible. This is a requirement for using the macro.</li> <li><code>A</code> has private members and is not a derived class. Hence, macro <code>NLOHMANN_DEFINE_TYPE_INTRUSIVE</code> is used.</li> <li>As <code>B</code> is a derived class, <code>NLOHMANN_DEFINE_TYPE_INTRUSIVE</code> is not applicable, but <code>NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE</code> must be used.</li> <li>The macro <code>NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE</code> is used <em>inside</em> the class use as <code>NLOHMANN_DEFINE_TYPE_INTRUSIVE</code>.</li> </ul> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../nlohmann_define_type_intrusive/ >NLOHMANN_DEFINE_TYPE_INTRUSIVE / NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT / NLOHMANN_DEFINE_TYPE_INTRUSIVE_ONLY_SERIALIZE</a> for similar macros that can be defined <em>inside</em> a non-derived type.</li> <li><a href=../nlohmann_define_type_non_intrusive/ >NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE / NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT / NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE</a> for similar macros that can be defined <em>outside</em> a non-derived type.</li> <li><a href=../../../features/arbitrary_types/ >Arbitrary Type Conversions</a> for an overview.</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ol> <li>Added in version 3.12.0.</li> <li>Added in version 3.12.0.</li> <li>Added in version 3.12.0.</li> <li>Added in version 3.12.0.</li> <li>Added in version 3.12.0.</li> <li>Added in version 3.12.0.</li> </ol> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 2013-2026 Niels Lohmann </div> </div> <div class=md-social> <a href="https://github.com/nlohmann" target="_blank" rel="noopener" title="github.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 512 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M173.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6m-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3m44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9M252.8 8C114.1 8 8 113.3 8 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C436.2 457.8 504 362.9 504 252 504 113.3 391.5 8 252.8 8M105.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1m-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7m32.4 35.6Line truncated
@@ -16,8 +16,8 @@
<span class=k>class</span><span class=w> </span><span class=nc>person</span>
<span class=p>{</span>
<span class=w> </span><span class=k>private</span><span class=o>:</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;John Doe&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;123 Fake St&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"John Doe"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"123 Fake St"</span><span class=p>;</span>
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>age</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=mi>-1</span><span class=p>;</span>
<span class=w> </span><span class=k>public</span><span class=o>:</span>
@@ -32,29 +32,29 @@
<span class=kt>int</span><span class=w> </span><span class=n>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>&quot;Ned Flanders&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>"Ned Flanders"</span><span class=p>,</span><span class=w> </span><span class=s>"744 Evergreen Terrace"</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=c1>// serialization: person -&gt; json</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>p</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;serialization: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"serialization: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=c1>// deserialization: json -&gt; person</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;age&quot;: 40, &quot;name&quot;: &quot;Homer Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"address": "742 Evergreen Terrace", "age": 40, "name": "Homer Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j2</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=c1>// incomplete deserialization:</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;name&quot;: &quot;Maggie Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"address": "742 Evergreen Terrace", "name": "Maggie Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>try</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j3</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=p>}</span>
<span class=w> </span><span class=k>catch</span><span class=w> </span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>exception</span><span class=o>&amp;</span><span class=w> </span><span class=n>e</span><span class=p>)</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;deserialization failed: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"deserialization failed: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=err>serializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=p>:</span><span class=w> </span><span class=p>{</span><span class=nt>&quot;address&quot;</span><span class=p>:</span><span class=s2>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=nt>&quot;age&quot;</span><span class=p>:</span><span class=mi>60</span><span class=p>,</span><span class=nt>&quot;name&quot;</span><span class=p>:</span><span class=s2>&quot;Ned Flanders&quot;</span><span class=p>}</span>
<span class=err>deserializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=w> </span><span class=kc>fa</span><span class=err>iled</span><span class=p>:</span><span class=w> </span><span class=p>[</span><span class=err>jso</span><span class=kc>n</span><span class=err>.excep</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=err>.ou</span><span class=kc>t</span><span class=err>_o</span><span class=kc>f</span><span class=err>_ra</span><span class=kc>n</span><span class=err>ge.</span><span class=mi>403</span><span class=p>]</span><span class=w> </span><span class=err>key</span><span class=w> </span><span class=err>&#39;age&#39;</span><span class=w> </span><span class=kc>n</span><span class=err>o</span><span class=kc>t</span><span class=w> </span><span class=kc>f</span><span class=err>ou</span><span class=kc>n</span><span class=err>d</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=err>serializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=p>:</span><span class=w> </span><span class=p>{</span><span class=nt>"address"</span><span class=p>:</span><span class=s2>"744 Evergreen Terrace"</span><span class=p>,</span><span class=nt>"age"</span><span class=p>:</span><span class=mi>60</span><span class=p>,</span><span class=nt>"name"</span><span class=p>:</span><span class=s2>"Ned Flanders"</span><span class=p>}</span>
<span class=err>deserializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=w> </span><span class=kc>fa</span><span class=err>iled</span><span class=p>:</span><span class=w> </span><span class=p>[</span><span class=err>jso</span><span class=kc>n</span><span class=err>.excep</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=err>.ou</span><span class=kc>t</span><span class=err>_o</span><span class=kc>f</span><span class=err>_ra</span><span class=kc>n</span><span class=err>ge.</span><span class=mi>403</span><span class=p>]</span><span class=w> </span><span class=err>key</span><span class=w> </span><span class=err>'age'</span><span class=w> </span><span class=kc>n</span><span class=err>o</span><span class=kc>t</span><span class=w> </span><span class=kc>f</span><span class=err>ou</span><span class=kc>n</span><span class=err>d</span>
</code></pre></div> <p>Notes:</p> <ul> <li><code>ns::person</code> is default-constructible. This is a requirement for using the macro.</li> <li><code>ns::person</code> has private member variables. This makes <code>NLOHMANN_DEFINE_TYPE_INTRUSIVE</code> applicable, but not <code>NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE</code>.</li> <li>The macro <code>NLOHMANN_DEFINE_TYPE_INTRUSIVE</code> is used <em>inside</em> the class.</li> <li>A missing key "age" in the deserialization yields an exception. To fall back to the default value, <code>NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT</code> can be used.</li> </ul> <p>The macro is equivalent to:</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
@@ -66,8 +66,8 @@
<span class=k>class</span><span class=w> </span><span class=nc>person</span>
<span class=p>{</span>
<span class=w> </span><span class=k>private</span><span class=o>:</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;John Doe&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;123 Fake St&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"John Doe"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"123 Fake St"</span><span class=p>;</span>
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>age</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=mi>-1</span><span class=p>;</span>
<span class=w> </span><span class=k>public</span><span class=o>:</span>
@@ -79,42 +79,42 @@
<span class=hll><span class=w> </span><span class=k>template</span><span class=o>&lt;</span><span class=k>typename</span><span class=w> </span><span class=nc>BasicJsonType</span><span class=o>&gt;</span>
</span><span class=hll><span class=w> </span><span class=k>friend</span><span class=w> </span><span class=kt>void</span><span class=w> </span><span class=n>to_json</span><span class=p>(</span><span class=n>BasicJsonType</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>,</span><span class=w> </span><span class=k>const</span><span class=w> </span><span class=n>person</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>)</span>
</span><span class=hll><span class=w> </span><span class=p>{</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;name&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;age&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"name"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"address"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"age"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=p>}</span>
</span><span class=hll>
</span><span class=hll><span class=w> </span><span class=k>template</span><span class=o>&lt;</span><span class=k>typename</span><span class=w> </span><span class=nc>BasicJsonType</span><span class=o>&gt;</span>
</span><span class=hll><span class=w> </span><span class=k>friend</span><span class=w> </span><span class=kt>void</span><span class=w> </span><span class=n>from_json</span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>BasicJsonType</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>,</span><span class=w> </span><span class=n>person</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>)</span>
</span><span class=hll><span class=w> </span><span class=p>{</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>at</span><span class=p>(</span><span class=s>&quot;name&quot;</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>at</span><span class=p>(</span><span class=s>&quot;address&quot;</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>at</span><span class=p>(</span><span class=s>&quot;age&quot;</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>at</span><span class=p>(</span><span class=s>"name"</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>at</span><span class=p>(</span><span class=s>"address"</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>at</span><span class=p>(</span><span class=s>"age"</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=p>}</span>
</span><span class=p>};</span>
<span class=p>}</span><span class=w> </span><span class=c1>// namespace ns</span>
<span class=kt>int</span><span class=w> </span><span class=n>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>&quot;Ned Flanders&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>"Ned Flanders"</span><span class=p>,</span><span class=w> </span><span class=s>"744 Evergreen Terrace"</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=c1>// serialization: person -&gt; json</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>p</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;serialization: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"serialization: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=c1>// deserialization: json -&gt; person</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;age&quot;: 40, &quot;name&quot;: &quot;Homer Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"address": "742 Evergreen Terrace", "age": 40, "name": "Homer Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j2</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=c1>// incomplete deserialization:</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;name&quot;: &quot;Maggie Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"address": "742 Evergreen Terrace", "name": "Maggie Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>try</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j3</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=p>}</span>
<span class=w> </span><span class=k>catch</span><span class=w> </span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>exception</span><span class=o>&amp;</span><span class=w> </span><span class=n>e</span><span class=p>)</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;deserialization failed: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"deserialization failed: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=p>}</span>
</code></pre></div> </details> <details class=example> <summary>Example (2): NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT</summary> <p>Consider the following complete example:</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
@@ -128,8 +128,8 @@
<span class=k>class</span><span class=w> </span><span class=nc>person</span>
<span class=p>{</span>
<span class=w> </span><span class=k>private</span><span class=o>:</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;John Doe&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;123 Fake St&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"John Doe"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"123 Fake St"</span><span class=p>;</span>
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>age</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=mi>-1</span><span class=p>;</span>
<span class=w> </span><span class=k>public</span><span class=o>:</span>
@@ -144,23 +144,23 @@
<span class=kt>int</span><span class=w> </span><span class=n>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>&quot;Ned Flanders&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>"Ned Flanders"</span><span class=p>,</span><span class=w> </span><span class=s>"744 Evergreen Terrace"</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=c1>// serialization: person -&gt; json</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>p</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;serialization: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"serialization: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=c1>// deserialization: json -&gt; person</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;age&quot;: 40, &quot;name&quot;: &quot;Homer Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"address": "742 Evergreen Terrace", "age": 40, "name": "Homer Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j2</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=c1>// incomplete deserialization:</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;name&quot;: &quot;Maggie Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"address": "742 Evergreen Terrace", "name": "Maggie Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j3</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;roundtrip: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>json</span><span class=p>(</span><span class=n>p3</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"roundtrip: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>json</span><span class=p>(</span><span class=n>p3</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=err>serializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=p>:</span><span class=w> </span><span class=p>{</span><span class=nt>&quot;address&quot;</span><span class=p>:</span><span class=s2>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=nt>&quot;age&quot;</span><span class=p>:</span><span class=mi>60</span><span class=p>,</span><span class=nt>&quot;name&quot;</span><span class=p>:</span><span class=s2>&quot;Ned Flanders&quot;</span><span class=p>}</span>
<span class=err>rou</span><span class=kc>n</span><span class=err>d</span><span class=kc>tr</span><span class=err>ip</span><span class=p>:</span><span class=w> </span><span class=p>{</span><span class=nt>&quot;address&quot;</span><span class=p>:</span><span class=s2>&quot;742 Evergreen Terrace&quot;</span><span class=p>,</span><span class=nt>&quot;age&quot;</span><span class=p>:</span><span class=mi>-1</span><span class=p>,</span><span class=nt>&quot;name&quot;</span><span class=p>:</span><span class=s2>&quot;Maggie Simpson&quot;</span><span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=err>serializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=p>:</span><span class=w> </span><span class=p>{</span><span class=nt>"address"</span><span class=p>:</span><span class=s2>"744 Evergreen Terrace"</span><span class=p>,</span><span class=nt>"age"</span><span class=p>:</span><span class=mi>60</span><span class=p>,</span><span class=nt>"name"</span><span class=p>:</span><span class=s2>"Ned Flanders"</span><span class=p>}</span>
<span class=err>rou</span><span class=kc>n</span><span class=err>d</span><span class=kc>tr</span><span class=err>ip</span><span class=p>:</span><span class=w> </span><span class=p>{</span><span class=nt>"address"</span><span class=p>:</span><span class=s2>"742 Evergreen Terrace"</span><span class=p>,</span><span class=nt>"age"</span><span class=p>:</span><span class=mi>-1</span><span class=p>,</span><span class=nt>"name"</span><span class=p>:</span><span class=s2>"Maggie Simpson"</span><span class=p>}</span>
</code></pre></div> <p>Notes:</p> <ul> <li><code>ns::person</code> is default-constructible. This is a requirement for using the macro.</li> <li><code>ns::person</code> has private member variables. This makes <code>NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT</code> applicable, but not <code>NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT</code>.</li> <li>The macro <code>NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT</code> is used <em>inside</em> the class.</li> <li>A missing key "age" in the deserialization does not yield an exception. Instead, the default value <code>-1</code> is used.</li> </ul> <p>The macro is equivalent to:</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
@@ -172,8 +172,8 @@
<span class=k>class</span><span class=w> </span><span class=nc>person</span>
<span class=p>{</span>
<span class=w> </span><span class=k>private</span><span class=o>:</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;John Doe&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;123 Fake St&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"John Doe"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"123 Fake St"</span><span class=p>;</span>
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>age</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=mi>-1</span><span class=p>;</span>
<span class=w> </span><span class=k>public</span><span class=o>:</span>
@@ -185,38 +185,38 @@
<span class=hll><span class=w> </span><span class=k>template</span><span class=o>&lt;</span><span class=k>typename</span><span class=w> </span><span class=nc>BasicJsonType</span><span class=o>&gt;</span>
</span><span class=hll><span class=w> </span><span class=k>friend</span><span class=w> </span><span class=kt>void</span><span class=w> </span><span class=n>to_json</span><span class=p>(</span><span class=n>BasicJsonType</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>,</span><span class=w> </span><span class=k>const</span><span class=w> </span><span class=n>person</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>)</span>
</span><span class=hll><span class=w> </span><span class=p>{</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;name&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;age&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"name"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"address"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"age"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=p>}</span>
</span><span class=hll>
</span><span class=hll><span class=w> </span><span class=k>template</span><span class=o>&lt;</span><span class=k>typename</span><span class=w> </span><span class=nc>BasicJsonType</span><span class=o>&gt;</span>
</span><span class=hll><span class=w> </span><span class=k>friend</span><span class=w> </span><span class=kt>void</span><span class=w> </span><span class=n>from_json</span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>BasicJsonType</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>,</span><span class=w> </span><span class=n>person</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>)</span>
</span><span class=hll><span class=w> </span><span class=p>{</span>
</span><span class=hll><span class=w> </span><span class=n>person</span><span class=w> </span><span class=n>nlohmann_json_default_obj</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>value</span><span class=p>(</span><span class=s>&quot;name&quot;</span><span class=p>,</span><span class=w> </span><span class=n>nlohmann_json_default_obj</span><span class=p>.</span><span class=n>name</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>value</span><span class=p>(</span><span class=s>&quot;address&quot;</span><span class=p>,</span><span class=w> </span><span class=n>nlohmann_json_default_obj</span><span class=p>.</span><span class=n>address</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>value</span><span class=p>(</span><span class=s>&quot;age&quot;</span><span class=p>,</span><span class=w> </span><span class=n>nlohmann_json_default_obj</span><span class=p>.</span><span class=n>age</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>value</span><span class=p>(</span><span class=s>"name"</span><span class=p>,</span><span class=w> </span><span class=n>nlohmann_json_default_obj</span><span class=p>.</span><span class=n>name</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>value</span><span class=p>(</span><span class=s>"address"</span><span class=p>,</span><span class=w> </span><span class=n>nlohmann_json_default_obj</span><span class=p>.</span><span class=n>address</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>value</span><span class=p>(</span><span class=s>"age"</span><span class=p>,</span><span class=w> </span><span class=n>nlohmann_json_default_obj</span><span class=p>.</span><span class=n>age</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=p>}</span>
</span><span class=p>};</span>
<span class=p>}</span><span class=w> </span><span class=c1>// namespace ns</span>
<span class=kt>int</span><span class=w> </span><span class=n>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>&quot;Ned Flanders&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>"Ned Flanders"</span><span class=p>,</span><span class=w> </span><span class=s>"744 Evergreen Terrace"</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=c1>// serialization: person -&gt; json</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>p</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;serialization: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"serialization: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=c1>// deserialization: json -&gt; person</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;age&quot;: 40, &quot;name&quot;: &quot;Homer Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"address": "742 Evergreen Terrace", "age": 40, "name": "Homer Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j2</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=c1>// incomplete deserialization:</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;name&quot;: &quot;Maggie Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"address": "742 Evergreen Terrace", "name": "Maggie Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j3</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;roundtrip: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>json</span><span class=p>(</span><span class=n>p3</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"roundtrip: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>json</span><span class=p>(</span><span class=n>p3</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> <p>Note how a default-initialized <code>person</code> object is used in the <code>from_json</code> to fill missing values.</p> </details> <details class=example> <summary>Example (3): NLOHMANN_DEFINE_TYPE_INTRUSIVE_ONLY_SERIALIZE</summary> <p>Consider the following complete example:</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
@@ -229,8 +229,8 @@
<span class=k>class</span><span class=w> </span><span class=nc>person</span>
<span class=p>{</span>
<span class=w> </span><span class=k>private</span><span class=o>:</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;John Doe&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;123 Fake St&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"John Doe"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"123 Fake St"</span><span class=p>;</span>
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>age</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=mi>-1</span><span class=p>;</span>
<span class=w> </span><span class=k>public</span><span class=o>:</span>
@@ -245,13 +245,13 @@
<span class=kt>int</span><span class=w> </span><span class=n>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>&quot;Ned Flanders&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>"Ned Flanders"</span><span class=p>,</span><span class=w> </span><span class=s>"744 Evergreen Terrace"</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=c1>// serialization: person -&gt; json</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>p</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;serialization: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"serialization: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=err>serializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=p>:</span><span class=w> </span><span class=p>{</span><span class=nt>&quot;address&quot;</span><span class=p>:</span><span class=s2>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=nt>&quot;age&quot;</span><span class=p>:</span><span class=mi>60</span><span class=p>,</span><span class=nt>&quot;name&quot;</span><span class=p>:</span><span class=s2>&quot;Ned Flanders&quot;</span><span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=err>serializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=p>:</span><span class=w> </span><span class=p>{</span><span class=nt>"address"</span><span class=p>:</span><span class=s2>"744 Evergreen Terrace"</span><span class=p>,</span><span class=nt>"age"</span><span class=p>:</span><span class=mi>60</span><span class=p>,</span><span class=nt>"name"</span><span class=p>:</span><span class=s2>"Ned Flanders"</span><span class=p>}</span>
</code></pre></div> <p>Notes:</p> <ul> <li><code>ns::person</code> is non-default-constructible. This allows this macro to be used instead of <code>NLOHMANN_DEFINE_TYPE_INTRUSIVE</code> and <code>NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT</code>.</li> <li><code>ns::person</code> has private member variables. This makes <code>NLOHMANN_DEFINE_TYPE_INTRUSIVE_ONLY_SERIALIZE</code> applicable, but not <code>NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE</code>.</li> <li>The macro <code>NLOHMANN_DEFINE_TYPE_INTRUSIVE_ONLY_SERIALIZE</code> is used <em>inside</em> the class.</li> </ul> <p>The macro is equivalent to:</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
@@ -263,8 +263,8 @@
<span class=k>class</span><span class=w> </span><span class=nc>person</span>
<span class=p>{</span>
<span class=w> </span><span class=k>private</span><span class=o>:</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;John Doe&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;123 Fake St&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"John Doe"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"123 Fake St"</span><span class=p>;</span>
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>age</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=mi>-1</span><span class=p>;</span>
<span class=w> </span><span class=k>public</span><span class=o>:</span>
@@ -276,19 +276,19 @@
<span class=hll><span class=w> </span><span class=k>template</span><span class=o>&lt;</span><span class=k>typename</span><span class=w> </span><span class=nc>BasicJsonType</span><span class=o>&gt;</span>
</span><span class=hll><span class=w> </span><span class=k>friend</span><span class=w> </span><span class=kt>void</span><span class=w> </span><span class=n>to_json</span><span class=p>(</span><span class=n>BasicJsonType</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>,</span><span class=w> </span><span class=k>const</span><span class=w> </span><span class=n>person</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>)</span>
</span><span class=hll><span class=w> </span><span class=p>{</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;name&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;age&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"name"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"address"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"age"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=p>}</span>
</span><span class=p>};</span>
<span class=p>}</span><span class=w> </span><span class=c1>// namespace ns</span>
<span class=kt>int</span><span class=w> </span><span class=n>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>&quot;Ned Flanders&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>"Ned Flanders"</span><span class=p>,</span><span class=w> </span><span class=s>"744 Evergreen Terrace"</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=c1>// serialization: person -&gt; json</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>p</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;serialization: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"serialization: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../nlohmann_define_type_non_intrusive/ >NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE</a> for a similar macro that can be defined <em>outside</em> the type.</li> <li><a href=../nlohmann_define_derived_type/ >NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_ONLY_SERIALIZE, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE</a> for similar macros for derived types</li> <li><a href=../../../features/arbitrary_types/ >Arbitrary Type Conversions</a> for an overview.</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ol> <li>Added in version 3.9.0.</li> <li>Added in version 3.11.0.</li> <li>Added in version 3.11.3.</li> </ol> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../nlohmann_define_type_non_intrusive/ >NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE</a> for a similar macro that can be defined <em>outside</em> the type.</li> <li><a href=../nlohmann_define_derived_type/ >NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_ONLY_SERIALIZE, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE</a> for similar macros for derived types</li> <li><a href=../../../features/arbitrary_types/ >Arbitrary Type Conversions</a> for an overview.</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ol> <li>Added in version 3.9.0.</li> <li>Added in version 3.11.0.</li> <li>Added in version 3.11.3.</li> </ol> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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@@ -25,29 +25,29 @@
<span class=kt>int</span><span class=w> </span><span class=n>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>&quot;Ned Flanders&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>"Ned Flanders"</span><span class=p>,</span><span class=w> </span><span class=s>"744 Evergreen Terrace"</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=c1>// serialization: person -&gt; json</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>p</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;serialization: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"serialization: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=c1>// deserialization: json -&gt; person</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;age&quot;: 40, &quot;name&quot;: &quot;Homer Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"address": "742 Evergreen Terrace", "age": 40, "name": "Homer Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j2</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=c1>// incomplete deserialization:</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;name&quot;: &quot;Maggie Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"address": "742 Evergreen Terrace", "name": "Maggie Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>try</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j3</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=p>}</span>
<span class=w> </span><span class=k>catch</span><span class=w> </span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>exception</span><span class=o>&amp;</span><span class=w> </span><span class=n>e</span><span class=p>)</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;deserialization failed: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"deserialization failed: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=err>serializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=p>:</span><span class=w> </span><span class=p>{</span><span class=nt>&quot;address&quot;</span><span class=p>:</span><span class=s2>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=nt>&quot;age&quot;</span><span class=p>:</span><span class=mi>60</span><span class=p>,</span><span class=nt>&quot;name&quot;</span><span class=p>:</span><span class=s2>&quot;Ned Flanders&quot;</span><span class=p>}</span>
<span class=err>deserializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=w> </span><span class=kc>fa</span><span class=err>iled</span><span class=p>:</span><span class=w> </span><span class=p>[</span><span class=err>jso</span><span class=kc>n</span><span class=err>.excep</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=err>.ou</span><span class=kc>t</span><span class=err>_o</span><span class=kc>f</span><span class=err>_ra</span><span class=kc>n</span><span class=err>ge.</span><span class=mi>403</span><span class=p>]</span><span class=w> </span><span class=err>key</span><span class=w> </span><span class=err>&#39;age&#39;</span><span class=w> </span><span class=kc>n</span><span class=err>o</span><span class=kc>t</span><span class=w> </span><span class=kc>f</span><span class=err>ou</span><span class=kc>n</span><span class=err>d</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=err>serializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=p>:</span><span class=w> </span><span class=p>{</span><span class=nt>"address"</span><span class=p>:</span><span class=s2>"744 Evergreen Terrace"</span><span class=p>,</span><span class=nt>"age"</span><span class=p>:</span><span class=mi>60</span><span class=p>,</span><span class=nt>"name"</span><span class=p>:</span><span class=s2>"Ned Flanders"</span><span class=p>}</span>
<span class=err>deserializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=w> </span><span class=kc>fa</span><span class=err>iled</span><span class=p>:</span><span class=w> </span><span class=p>[</span><span class=err>jso</span><span class=kc>n</span><span class=err>.excep</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=err>.ou</span><span class=kc>t</span><span class=err>_o</span><span class=kc>f</span><span class=err>_ra</span><span class=kc>n</span><span class=err>ge.</span><span class=mi>403</span><span class=p>]</span><span class=w> </span><span class=err>key</span><span class=w> </span><span class=err>'age'</span><span class=w> </span><span class=kc>n</span><span class=err>o</span><span class=kc>t</span><span class=w> </span><span class=kc>f</span><span class=err>ou</span><span class=kc>n</span><span class=err>d</span>
</code></pre></div> <p>Notes:</p> <ul> <li><code>ns::person</code> is default-constructible. This is a requirement for using the macro.</li> <li><code>ns::person</code> has only public member variables. This makes <code>NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE</code> applicable.</li> <li>The macro <code>NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE</code> is used <em>outside</em> the class, but <em>inside</em> its namespace <code>ns</code>.</li> <li>A missing key "age" in the deserialization yields an exception. To fall back to the default value, <code>NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT</code> can be used.</li> </ul> <p>The macro is equivalent to:</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
@@ -66,41 +66,41 @@
<span class=hll><span class=k>template</span><span class=o>&lt;</span><span class=k>typename</span><span class=w> </span><span class=nc>BasicJsonType</span><span class=o>&gt;</span>
</span><span class=hll><span class=kt>void</span><span class=w> </span><span class=n>to_json</span><span class=p>(</span><span class=n>BasicJsonType</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>,</span><span class=w> </span><span class=k>const</span><span class=w> </span><span class=n>person</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>)</span>
</span><span class=hll><span class=p>{</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;name&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;age&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"name"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"address"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"age"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=p>;</span>
</span><span class=hll><span class=p>}</span>
</span><span class=hll>
</span><span class=hll><span class=k>template</span><span class=o>&lt;</span><span class=k>typename</span><span class=w> </span><span class=nc>BasicJsonType</span><span class=o>&gt;</span>
</span><span class=hll><span class=kt>void</span><span class=w> </span><span class=n>from_json</span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>BasicJsonType</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>,</span><span class=w> </span><span class=n>person</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>)</span>
</span><span class=hll><span class=p>{</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>at</span><span class=p>(</span><span class=s>&quot;name&quot;</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>at</span><span class=p>(</span><span class=s>&quot;address&quot;</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>at</span><span class=p>(</span><span class=s>&quot;age&quot;</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>at</span><span class=p>(</span><span class=s>"name"</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>at</span><span class=p>(</span><span class=s>"address"</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>at</span><span class=p>(</span><span class=s>"age"</span><span class=p>);</span>
</span><span class=hll><span class=p>}</span>
</span><span class=p>}</span><span class=w> </span><span class=c1>// namespace ns</span>
<span class=kt>int</span><span class=w> </span><span class=n>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>&quot;Ned Flanders&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>"Ned Flanders"</span><span class=p>,</span><span class=w> </span><span class=s>"744 Evergreen Terrace"</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=c1>// serialization: person -&gt; json</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>p</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;serialization: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"serialization: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=c1>// deserialization: json -&gt; person</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;age&quot;: 40, &quot;name&quot;: &quot;Homer Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"address": "742 Evergreen Terrace", "age": 40, "name": "Homer Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j2</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=c1>// incomplete deserialization:</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;name&quot;: &quot;Maggie Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"address": "742 Evergreen Terrace", "name": "Maggie Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>try</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j3</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=p>}</span>
<span class=w> </span><span class=k>catch</span><span class=w> </span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>exception</span><span class=o>&amp;</span><span class=w> </span><span class=n>e</span><span class=p>)</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;deserialization failed: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"deserialization failed: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=p>}</span>
</code></pre></div> </details> <details class=example> <summary>Example (2): NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT</summary> <p>Consider the following complete example:</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
@@ -113,8 +113,8 @@
<span class=p>{</span>
<span class=k>struct</span><span class=w> </span><span class=nc>person</span>
<span class=p>{</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;John Doe&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;123 Fake St&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"John Doe"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"123 Fake St"</span><span class=p>;</span>
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>age</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=mi>-1</span><span class=p>;</span>
<span class=w> </span><span class=n>person</span><span class=p>()</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=k>default</span><span class=p>;</span>
@@ -128,23 +128,23 @@
<span class=kt>int</span><span class=w> </span><span class=n>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>&quot;Ned Flanders&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>"Ned Flanders"</span><span class=p>,</span><span class=w> </span><span class=s>"744 Evergreen Terrace"</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=c1>// serialization: person -&gt; json</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>p</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;serialization: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"serialization: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=c1>// deserialization: json -&gt; person</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;age&quot;: 40, &quot;name&quot;: &quot;Homer Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"address": "742 Evergreen Terrace", "age": 40, "name": "Homer Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j2</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=c1>// incomplete deserialization:</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;name&quot;: &quot;Maggie Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"address": "742 Evergreen Terrace", "name": "Maggie Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j3</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;roundtrip: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>json</span><span class=p>(</span><span class=n>p3</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"roundtrip: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>json</span><span class=p>(</span><span class=n>p3</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=err>serializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=p>:</span><span class=w> </span><span class=p>{</span><span class=nt>&quot;address&quot;</span><span class=p>:</span><span class=s2>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=nt>&quot;age&quot;</span><span class=p>:</span><span class=mi>60</span><span class=p>,</span><span class=nt>&quot;name&quot;</span><span class=p>:</span><span class=s2>&quot;Ned Flanders&quot;</span><span class=p>}</span>
<span class=err>rou</span><span class=kc>n</span><span class=err>d</span><span class=kc>tr</span><span class=err>ip</span><span class=p>:</span><span class=w> </span><span class=p>{</span><span class=nt>&quot;address&quot;</span><span class=p>:</span><span class=s2>&quot;742 Evergreen Terrace&quot;</span><span class=p>,</span><span class=nt>&quot;age&quot;</span><span class=p>:</span><span class=mi>-1</span><span class=p>,</span><span class=nt>&quot;name&quot;</span><span class=p>:</span><span class=s2>&quot;Maggie Simpson&quot;</span><span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=err>serializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=p>:</span><span class=w> </span><span class=p>{</span><span class=nt>"address"</span><span class=p>:</span><span class=s2>"744 Evergreen Terrace"</span><span class=p>,</span><span class=nt>"age"</span><span class=p>:</span><span class=mi>60</span><span class=p>,</span><span class=nt>"name"</span><span class=p>:</span><span class=s2>"Ned Flanders"</span><span class=p>}</span>
<span class=err>rou</span><span class=kc>n</span><span class=err>d</span><span class=kc>tr</span><span class=err>ip</span><span class=p>:</span><span class=w> </span><span class=p>{</span><span class=nt>"address"</span><span class=p>:</span><span class=s2>"742 Evergreen Terrace"</span><span class=p>,</span><span class=nt>"age"</span><span class=p>:</span><span class=mi>-1</span><span class=p>,</span><span class=nt>"name"</span><span class=p>:</span><span class=s2>"Maggie Simpson"</span><span class=p>}</span>
</code></pre></div> <p>Notes:</p> <ul> <li><code>ns::person</code> is default-constructible. This is a requirement for using the macro.</li> <li><code>ns::person</code> has only public member variables. This makes <code>NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT</code> applicable.</li> <li>The macro <code>NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT</code> is used <em>outside</em> the class, but <em>inside</em> its namespace <code>ns</code>.</li> <li>A missing key "age" in the deserialization does not yield an exception. Instead, the default value <code>-1</code> is used.</li> </ul> <p>The macro is equivalent to:</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
@@ -155,8 +155,8 @@
<span class=p>{</span>
<span class=k>struct</span><span class=w> </span><span class=nc>person</span>
<span class=p>{</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;John Doe&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;123 Fake St&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"John Doe"</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>string</span><span class=w> </span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"123 Fake St"</span><span class=p>;</span>
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>age</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=mi>-1</span><span class=p>;</span>
<span class=w> </span><span class=n>person</span><span class=p>()</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=k>default</span><span class=p>;</span>
@@ -168,37 +168,37 @@
<span class=hll><span class=k>template</span><span class=o>&lt;</span><span class=k>typename</span><span class=w> </span><span class=nc>BasicJsonType</span><span class=o>&gt;</span>
</span><span class=hll><span class=kt>void</span><span class=w> </span><span class=n>to_json</span><span class=p>(</span><span class=n>BasicJsonType</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>,</span><span class=w> </span><span class=k>const</span><span class=w> </span><span class=n>person</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>)</span>
</span><span class=hll><span class=p>{</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;name&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;age&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"name"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"address"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"age"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=p>;</span>
</span><span class=hll><span class=p>}</span>
</span><span class=hll>
</span><span class=hll><span class=k>template</span><span class=o>&lt;</span><span class=k>typename</span><span class=w> </span><span class=nc>BasicJsonType</span><span class=o>&gt;</span>
</span><span class=hll><span class=kt>void</span><span class=w> </span><span class=n>from_json</span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>BasicJsonType</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>,</span><span class=w> </span><span class=n>person</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>)</span>
</span><span class=hll><span class=p>{</span>
</span><span class=hll><span class=w> </span><span class=n>person</span><span class=w> </span><span class=n>nlohmann_json_default_obj</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>value</span><span class=p>(</span><span class=s>&quot;name&quot;</span><span class=p>,</span><span class=w> </span><span class=n>nlohmann_json_default_obj</span><span class=p>.</span><span class=n>name</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>value</span><span class=p>(</span><span class=s>&quot;address&quot;</span><span class=p>,</span><span class=w> </span><span class=n>nlohmann_json_default_obj</span><span class=p>.</span><span class=n>address</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>value</span><span class=p>(</span><span class=s>&quot;age&quot;</span><span class=p>,</span><span class=w> </span><span class=n>nlohmann_json_default_obj</span><span class=p>.</span><span class=n>age</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>value</span><span class=p>(</span><span class=s>"name"</span><span class=p>,</span><span class=w> </span><span class=n>nlohmann_json_default_obj</span><span class=p>.</span><span class=n>name</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>value</span><span class=p>(</span><span class=s>"address"</span><span class=p>,</span><span class=w> </span><span class=n>nlohmann_json_default_obj</span><span class=p>.</span><span class=n>address</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>value</span><span class=p>(</span><span class=s>"age"</span><span class=p>,</span><span class=w> </span><span class=n>nlohmann_json_default_obj</span><span class=p>.</span><span class=n>age</span><span class=p>);</span>
</span><span class=hll><span class=p>}</span>
</span><span class=p>}</span><span class=w> </span><span class=c1>// namespace ns</span>
<span class=kt>int</span><span class=w> </span><span class=n>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>&quot;Ned Flanders&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>"Ned Flanders"</span><span class=p>,</span><span class=w> </span><span class=s>"744 Evergreen Terrace"</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=c1>// serialization: person -&gt; json</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>p</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;serialization: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"serialization: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=c1>// deserialization: json -&gt; person</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;age&quot;: 40, &quot;name&quot;: &quot;Homer Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"address": "742 Evergreen Terrace", "age": 40, "name": "Homer Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j2</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=c1>// incomplete deserialization:</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;name&quot;: &quot;Maggie Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"address": "742 Evergreen Terrace", "name": "Maggie Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j3</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;roundtrip: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>json</span><span class=p>(</span><span class=n>p3</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"roundtrip: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>json</span><span class=p>(</span><span class=n>p3</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> <p>Note how a default-initialized <code>person</code> object is used in the <code>from_json</code> to fill missing values.</p> </details> <details class=example> <summary>Example (3): NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE</summary> <p>Consider the following complete example:</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
@@ -220,13 +220,13 @@
<span class=kt>int</span><span class=w> </span><span class=n>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>&quot;Ned Flanders&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>"Ned Flanders"</span><span class=p>,</span><span class=w> </span><span class=s>"744 Evergreen Terrace"</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=c1>// serialization: person -&gt; json</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>p</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;serialization: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"serialization: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=err>serializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=p>:</span><span class=w> </span><span class=p>{</span><span class=nt>&quot;address&quot;</span><span class=p>:</span><span class=s2>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=nt>&quot;age&quot;</span><span class=p>:</span><span class=mi>60</span><span class=p>,</span><span class=nt>&quot;name&quot;</span><span class=p>:</span><span class=s2>&quot;Ned Flanders&quot;</span><span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=err>serializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=p>:</span><span class=w> </span><span class=p>{</span><span class=nt>"address"</span><span class=p>:</span><span class=s2>"744 Evergreen Terrace"</span><span class=p>,</span><span class=nt>"age"</span><span class=p>:</span><span class=mi>60</span><span class=p>,</span><span class=nt>"name"</span><span class=p>:</span><span class=s2>"Ned Flanders"</span><span class=p>}</span>
</code></pre></div> <p>Notes:</p> <ul> <li><code>ns::person</code> is non-default-constructible. This allows this macro to be used instead of <code>NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE</code> and <code>NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT</code>.</li> <li><code>ns::person</code> has only public member variables. This makes <code>NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE</code> applicable.</li> <li>The macro <code>NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE</code> is used <em>outside</em> the class, but <em>inside</em> its namespace <code>ns</code>.</li> </ul> <p>The macro is equivalent to:</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
@@ -245,18 +245,18 @@
<span class=hll><span class=k>template</span><span class=o>&lt;</span><span class=k>typename</span><span class=w> </span><span class=nc>BasicJsonType</span><span class=o>&gt;</span>
</span><span class=hll><span class=kt>void</span><span class=w> </span><span class=n>to_json</span><span class=p>(</span><span class=n>BasicJsonType</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>,</span><span class=w> </span><span class=k>const</span><span class=w> </span><span class=n>person</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>)</span>
</span><span class=hll><span class=p>{</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;name&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;address&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;age&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"name"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"address"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"age"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=p>;</span>
</span><span class=hll><span class=p>}</span>
</span><span class=p>}</span><span class=w> </span><span class=c1>// namespace ns</span>
<span class=kt>int</span><span class=w> </span><span class=n>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>&quot;Ned Flanders&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>"Ned Flanders"</span><span class=p>,</span><span class=w> </span><span class=s>"744 Evergreen Terrace"</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=c1>// serialization: person -&gt; json</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>p</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;serialization: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"serialization: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../nlohmann_define_type_intrusive/ >NLOHMANN_DEFINE_TYPE_INTRUSIVE, NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_TYPE_INTRUSIVE_ONLY_SERIALIZE</a> for a similar macro that can be defined <em>inside</em> the type.</li> <li><a href=../nlohmann_define_derived_type/ >NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_ONLY_SERIALIZE, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE</a> for similar macros for derived types</li> <li><a href=../../../features/arbitrary_types/ >Arbitrary Type Conversions</a> for an overview.</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ol> <li>Added in version 3.9.0.</li> <li>Added in version 3.11.0.</li> <li>Added in version 3.11.3.</li> </ol> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../nlohmann_define_type_intrusive/ >NLOHMANN_DEFINE_TYPE_INTRUSIVE, NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_TYPE_INTRUSIVE_ONLY_SERIALIZE</a> for a similar macro that can be defined <em>inside</em> the type.</li> <li><a href=../nlohmann_define_derived_type/ >NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_ONLY_SERIALIZE, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE</a> for similar macros for derived types</li> <li><a href=../../../features/arbitrary_types/ >Arbitrary Type Conversions</a> for an overview.</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ol> <li>Added in version 3.9.0.</li> <li>Added in version 3.11.0.</li> <li>Added in version 3.11.3.</li> </ol> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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<!doctype html><html lang=en class=no-js> <head><meta charset=utf-8><meta name=viewport content="width=device-width,initial-scale=1"><meta name=author content="Niels Lohmann"><link href="https://json.nlohmann.me/api/macros/nlohmann_define_type_with_names/" rel="canonical"><link href=../nlohmann_define_type_non_intrusive/ rel=prev><link href=../nlohmann_json_namespace/ rel=next><link rel=icon href=../../../assets/images/favicon.png><meta name=generator content="mkdocs-1.6.1, mkdocs-material-9.7.7"><title>NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_NAMES, NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT_WITH_NAMES, NLOHMANN_DEFINE_TYPE_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_NAMES, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT_WITH_NAMES, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_DEFAULT_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_DEFAULT_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES - JSON for Modern C++</title><link rel=stylesheet href=../../../assets/stylesheets/main.ec1eaa64.min.css><link rel=stylesheet href=../../../assets/stylesheets/palette.ab4e12ef.min.css><link rel="stylesheet" href="../../../assets/external/fonts.googleapis.com/css.61a430c9.css"><style>:root{--md-text-font:"Roboto";--md-code-font:"JetBrains Mono"}</style><link rel=stylesheet href=../../../css/custom.css><script>__md_scope=new URL("../../..",location),__md_hash=e=>[...e].reduce(((e,_)=>(e<<5)-e+_.charCodeAt(0)),0),__md_get=(e,_=localStorage,t=__md_scope)=>JSON.parse(_.getItem(t.pathname+"."+e)),__md_set=(e,_,t=localStorage,a=__md_scope)=>{try{t.setItem(a.pathname+"."+e,JSON.stringify(_))}catch(e){}}</script></head> <body dir=ltr data-md-color-scheme=default data-md-color-primary=indigo data-md-color-accent=indigo> <input class=md-toggle data-md-toggle=drawer type=checkbox id=__drawer autocomplete=off> <input class=md-toggle data-md-toggle=search type=checkbox id=__search autocomplete=off> <label class=md-overlay for=__drawer></label> <div data-md-component=skip> <a href=#parameters class=md-skip> Skip to content </a> </div> <div data-md-component=announce> </div> <header class=md-header data-md-component=header> <nav class="md-header__inner md-grid" aria-label=Header> <a href=../../.. title="JSON for Modern C++" class="md-header__button md-logo" aria-label="JSON for Modern C++" data-md-component=logo> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M12 8a3 3 0 0 0 3-3 3 3 0 0 0-3-3 3 3 0 0 0-3 3 3 3 0 0 0 3 3m0 3.54C9.64 9.35 6.5 8 3 8v11c3.5 0 6.64 1.35 9 3.54 2.36-2.19 5.5-3.54 9-3.54V8c-3.5 0-6.64 1.35-9 3.54"/></svg> </a> <label class="md-header__button md-icon" for=__drawer> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M3 6h18v2H3zm0 5h18v2H3zm0 5h18v2H3z"/></svg> </label> <div class=md-header__title data-md-component=header-title> <div class=md-header__ellipsis> <div class=md-header__topic> <span class=md-ellipsis> JSON for Modern C++ </span> </div> <div class=md-header__topic data-md-component=header-topic> <span class=md-ellipsis> NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_NAMES, NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT_WITH_NAMES, NLOHMANN_DEFINE_TYPE_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_NAMES, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT_WITH_NAMES, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_DEFAULT_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_DEFAULT_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES </span> </div> </div> </div> <form class=md-header__option data-md-component=palette> <input class=md-option data-md-color-media="(prefers-color-scheme: light)" data-md-color-scheme=default data-md-color-primary=indigo data-md-color-accent=indigo aria-label="Switch to dark mode" type=radio name=__palette id=__palette_0> <label class="md-header__button md-icon" title="Switch to dark mode" for=__palette_1 hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M12 8a4 4 0 0 0-4 4 4 4 0 0 0 4 4 4 4 0 0 0 4-4 4 4 0 0 0-4-4m0 10a6 6 0 0 1-6-6 6 6 0 0 1 6-6 6 6 0 0 1 6 6 6 6 0 0 1-6 6m8-9.31V4h-4.69L12 .69 8.69 4H4v4.69L.69 12 4 15.31V20h4.69L12 23.31 15.31 20H20v-4.69L23.31 12z"/></svg> </label> <input class=md-option data-md-color-media="(prefers-color-scheme: dark)" data-md-color-scheme=slate data-md-color-primary=indigo data-md-color-accent=indigo aria-label="Switch to light mode" type=radio name=__palette id=__palette_1> <label class="md-header__buLine truncated
<span class=cp>#define NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT_WITH_NAMES(type, &quot;json_member_name&quot;, member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_TYPE_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES(type, &quot;json_member_name&quot;, member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_NAMES(type, &quot;json_member_name&quot;, member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT_WITH_NAMES(type, &quot;json_member_name&quot;, member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES(type, &quot;json_member_name&quot;, member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_NAMES(type, base_type, &quot;json_member_name&quot;, member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_DEFAULT_WITH_NAMES(type, base_type, &quot;json_member_name&quot;, member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES(type, base_type, &quot;json_member_name&quot;, member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_NAMES(type, base_type, &quot;json_member_name&quot;, member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_DEFAULT_WITH_NAMES(type, base_type, &quot;json_member_name&quot;, member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES(type, base_type, &quot;json_member_name&quot;, member...)</span>
<!doctype html><html lang=en class=no-js> <head><meta charset=utf-8><meta name=viewport content="width=device-width,initial-scale=1"><meta name=author content="Niels Lohmann"><link href="https://json.nlohmann.me/api/macros/nlohmann_define_type_with_names/" rel="canonical"><link href=../nlohmann_define_type_non_intrusive/ rel=prev><link href=../nlohmann_json_namespace/ rel=next><link rel=icon href=../../../assets/images/favicon.png><meta name=generator content="mkdocs-1.6.1, mkdocs-material-9.7.7"><title>NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_NAMES, NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT_WITH_NAMES, NLOHMANN_DEFINE_TYPE_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_NAMES, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT_WITH_NAMES, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_DEFAULT_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_DEFAULT_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES - JSON for Modern C++</title><link rel=stylesheet href=../../../assets/stylesheets/main.ec1eaa64.min.css><link rel=stylesheet href=../../../assets/stylesheets/palette.ab4e12ef.min.css><link rel="stylesheet" href="../../../assets/external/fonts.googleapis.com/css.61a430c9.css"><style>:root{--md-text-font:"Roboto";--md-code-font:"JetBrains Mono"}</style><link rel=stylesheet href=../../../css/custom.css><script>__md_scope=new URL("../../..",location),__md_hash=e=>[...e].reduce(((e,_)=>(e<<5)-e+_.charCodeAt(0)),0),__md_get=(e,_=localStorage,t=__md_scope)=>JSON.parse(_.getItem(t.pathname+"."+e)),__md_set=(e,_,t=localStorage,a=__md_scope)=>{try{t.setItem(a.pathname+"."+e,JSON.stringify(_))}catch(e){}}</script></head> <body dir=ltr data-md-color-scheme=default data-md-color-primary=indigo data-md-color-accent=indigo> <input class=md-toggle data-md-toggle=drawer type=checkbox id=__drawer autocomplete=off> <input class=md-toggle data-md-toggle=search type=checkbox id=__search autocomplete=off> <label class=md-overlay for=__drawer></label> <div data-md-component=skip> <a href=#parameters class=md-skip> Skip to content </a> </div> <div data-md-component=announce> </div> <header class=md-header data-md-component=header> <nav class="md-header__inner md-grid" aria-label=Header> <a href=../../.. title="JSON for Modern C++" class="md-header__button md-logo" aria-label="JSON for Modern C++" data-md-component=logo> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M12 8a3 3 0 0 0 3-3 3 3 0 0 0-3-3 3 3 0 0 0-3 3 3 3 0 0 0 3 3m0 3.54C9.64 9.35 6.5 8 3 8v11c3.5 0 6.64 1.35 9 3.54 2.36-2.19 5.5-3.54 9-3.54V8c-3.5 0-6.64 1.35-9 3.54"/></svg> </a> <label class="md-header__button md-icon" for=__drawer> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M3 6h18v2H3zm0 5h18v2H3zm0 5h18v2H3z"/></svg> </label> <div class=md-header__title data-md-component=header-title> <div class=md-header__ellipsis> <div class=md-header__topic> <span class=md-ellipsis> JSON for Modern C++ </span> </div> <div class=md-header__topic data-md-component=header-topic> <span class=md-ellipsis> NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_NAMES, NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT_WITH_NAMES, NLOHMANN_DEFINE_TYPE_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_NAMES, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT_WITH_NAMES, NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_DEFAULT_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_DEFAULT_WITH_NAMES, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES </span> </div> </div> </div> <form class=md-header__option data-md-component=palette> <input class=md-option data-md-color-media="(prefers-color-scheme: light)" data-md-color-scheme=default data-md-color-primary=indigo data-md-color-accent=indigo aria-label="Switch to dark mode" type=radio name=__palette id=__palette_0> <label class="md-header__button md-icon" title="Switch to dark mode" for=__palette_1 hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M12 8a4 4 0 0 0-4 4 4 4 0 0 0 4 4 4 4 0 0 0 4-4 4 4 0 0 0-4-4m0 10a6 6 0 0 1-6-6 6 6 0 0 1 6-6 6 6 0 0 1 6 6 6 6 0 0 1-6 6m8-9.31V4h-4.69L12 .69 8.69 4H4v4.69L.69 12 4 15.31V20h4.69L12 23.31 15.31 20H20v-4.69L23.31 12z"/></svg> </label> <input class=md-option data-md-color-media="(prefers-color-scheme: dark)" data-md-color-scheme=slate data-md-color-primary=indigo data-md-color-accent=indigo aria-label="Switch to light mode" type=radio name=__palette id=__palette_1> <label class="md-header__buLine truncated
<span class=cp>#define NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT_WITH_NAMES(type, "json_member_name", member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_TYPE_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES(type, "json_member_name", member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_NAMES(type, "json_member_name", member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT_WITH_NAMES(type, "json_member_name", member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES(type, "json_member_name", member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_NAMES(type, base_type, "json_member_name", member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_DEFAULT_WITH_NAMES(type, base_type, "json_member_name", member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES(type, base_type, "json_member_name", member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_NAMES(type, base_type, "json_member_name", member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_DEFAULT_WITH_NAMES(type, base_type, "json_member_name", member...)</span>
<span class=cp>#define NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES(type, base_type, "json_member_name", member...)</span>
</code></pre></div> <p>These macros can be used in case you want to use the custom names for the member variables in the resulting <abbr title="JavaScript Object Notation">JSON</abbr>. They behave exactly as their non-<code>WITH_NAMES</code> counterparts, but require an additional parameter for each member variable which will be used in <abbr title="JavaScript Object Notation">JSON</abbr>. Both serialization and deserialization will only use the custom names for <abbr title="JavaScript Object Notation">JSON</abbr>, the names of the member variables themselves will be ignored.</p> <p>Using the named conversion macros will halve the maximum number of member variables from 63 to 31.</p> <p>For further information please refer to the corresponding macros without <code>WITH_NAMES</code>.</p> <h2 id=parameters>Parameters<a class=headerlink href=#parameters title="Permanent link">&para;</a></h2> <dl> <dt><code>type</code> (in)</dt> <dd>name of the type (class, struct) to serialize/deserialize</dd> <dt><code>base_type</code> (in)</dt> <dd>name of the base type (class, struct) <code>type</code> is derived from (used only in <code>DEFINE_DERIVED_TYPE</code> macros)</dd> <dt><code>json_member_name</code> (in)</dt> <dd>the string that will be used as the name for the next value</dd> <dt><code>member</code> (in)</dt> <dd>name of the member variable to serialize/deserialize</dd> </dl> <h2 id=examples>Examples<a class=headerlink href=#examples title="Permanent link">&para;</a></h2> <details class=example> <summary>Example (1): NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_NAMES</summary> <p>Consider the following complete example:</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
@@ -25,34 +25,34 @@
<span class=w> </span><span class=kt>int</span><span class=w> </span><span class=n>age</span><span class=p>;</span>
<span class=p>};</span>
<span class=hll><span class=n>NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_NAMES</span><span class=p>(</span><span class=n>person</span><span class=p>,</span><span class=w> </span><span class=s>&quot;json_name&quot;</span><span class=p>,</span><span class=w> </span><span class=n>name</span><span class=p>,</span><span class=w> </span><span class=s>&quot;json_address&quot;</span><span class=p>,</span><span class=w> </span><span class=n>address</span><span class=p>,</span><span class=w> </span><span class=s>&quot;json_age&quot;</span><span class=p>,</span><span class=w> </span><span class=n>age</span><span class=p>)</span>
<span class=hll><span class=n>NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_NAMES</span><span class=p>(</span><span class=n>person</span><span class=p>,</span><span class=w> </span><span class=s>"json_name"</span><span class=p>,</span><span class=w> </span><span class=n>name</span><span class=p>,</span><span class=w> </span><span class=s>"json_address"</span><span class=p>,</span><span class=w> </span><span class=n>address</span><span class=p>,</span><span class=w> </span><span class=s>"json_age"</span><span class=p>,</span><span class=w> </span><span class=n>age</span><span class=p>)</span>
</span><span class=p>}</span><span class=w> </span><span class=c1>// namespace ns</span>
<span class=kt>int</span><span class=w> </span><span class=n>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>&quot;Ned Flanders&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>"Ned Flanders"</span><span class=p>,</span><span class=w> </span><span class=s>"744 Evergreen Terrace"</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=c1>// serialization: person -&gt; json</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>p</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;serialization: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"serialization: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=c1>// deserialization: json -&gt; person</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;json_address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;json_age&quot;: 40, &quot;json_name&quot;: &quot;Homer Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"json_address": "742 Evergreen Terrace", "json_age": 40, "json_name": "Homer Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j2</span><span class=p>.</span><span class=k>template</span><span class=w> </span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=c1>// incomplete deserialization:</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;json_address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;json_name&quot;: &quot;Maggie Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"json_address": "742 Evergreen Terrace", "json_name": "Maggie Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>try</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j3</span><span class=p>.</span><span class=k>template</span><span class=w> </span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=p>}</span>
<span class=w> </span><span class=k>catch</span><span class=w> </span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>exception</span><span class=o>&amp;</span><span class=w> </span><span class=n>e</span><span class=p>)</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;deserialization failed: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"deserialization failed: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=err>serializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=p>:</span><span class=w> </span><span class=p>{</span><span class=nt>&quot;json_address&quot;</span><span class=p>:</span><span class=s2>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=nt>&quot;json_age&quot;</span><span class=p>:</span><span class=mi>60</span><span class=p>,</span><span class=nt>&quot;json_name&quot;</span><span class=p>:</span><span class=s2>&quot;Ned Flanders&quot;</span><span class=p>}</span>
<span class=err>deserializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=w> </span><span class=kc>fa</span><span class=err>iled</span><span class=p>:</span><span class=w> </span><span class=p>[</span><span class=err>jso</span><span class=kc>n</span><span class=err>.excep</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=err>.ou</span><span class=kc>t</span><span class=err>_o</span><span class=kc>f</span><span class=err>_ra</span><span class=kc>n</span><span class=err>ge.</span><span class=mi>403</span><span class=p>]</span><span class=w> </span><span class=err>key</span><span class=w> </span><span class=err>&#39;jso</span><span class=kc>n</span><span class=err>_age&#39;</span><span class=w> </span><span class=kc>n</span><span class=err>o</span><span class=kc>t</span><span class=w> </span><span class=kc>f</span><span class=err>ou</span><span class=kc>n</span><span class=err>d</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=err>serializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=p>:</span><span class=w> </span><span class=p>{</span><span class=nt>"json_address"</span><span class=p>:</span><span class=s2>"744 Evergreen Terrace"</span><span class=p>,</span><span class=nt>"json_age"</span><span class=p>:</span><span class=mi>60</span><span class=p>,</span><span class=nt>"json_name"</span><span class=p>:</span><span class=s2>"Ned Flanders"</span><span class=p>}</span>
<span class=err>deserializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=w> </span><span class=kc>fa</span><span class=err>iled</span><span class=p>:</span><span class=w> </span><span class=p>[</span><span class=err>jso</span><span class=kc>n</span><span class=err>.excep</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=err>.ou</span><span class=kc>t</span><span class=err>_o</span><span class=kc>f</span><span class=err>_ra</span><span class=kc>n</span><span class=err>ge.</span><span class=mi>403</span><span class=p>]</span><span class=w> </span><span class=err>key</span><span class=w> </span><span class=err>'jso</span><span class=kc>n</span><span class=err>_age'</span><span class=w> </span><span class=kc>n</span><span class=err>o</span><span class=kc>t</span><span class=w> </span><span class=kc>f</span><span class=err>ou</span><span class=kc>n</span><span class=err>d</span>
</code></pre></div> <p>Notes:</p> <ul> <li><code>ns::person</code> is default-constructible. This is a requirement for using the macro.</li> <li><code>ns::person</code> has only public member variables. This makes <code>NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_NAMES</code> applicable.</li> <li>The macro <code>NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_NAMES</code> is used <em>outside</em> the class, but <em>inside</em> its namespace <code>ns</code>.</li> <li>A missing key "age" in the deserialization yields an exception. To fall back to the default value, <code>NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT_WITH_NAMES</code> can be used.</li> </ul> <p>The macro is equivalent to:</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
@@ -71,41 +71,41 @@
<span class=hll><span class=k>template</span><span class=w> </span><span class=o>&lt;</span><span class=k>typename</span><span class=w> </span><span class=nc>BasicJsonType</span><span class=p>,</span><span class=w> </span><span class=n>nlohmann</span><span class=o>::</span><span class=n>detail</span><span class=o>::</span><span class=n>enable_if_t</span><span class=o>&lt;</span><span class=n>nlohmann</span><span class=o>::</span><span class=n>detail</span><span class=o>::</span><span class=n>is_basic_json</span><span class=o>&lt;</span><span class=n>BasicJsonType</span><span class=o>&gt;::</span><span class=n>value</span><span class=p>,</span><span class=w> </span><span class=kt>int</span><span class=o>&gt;</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=mi>0</span><span class=o>&gt;</span>
</span><span class=hll><span class=kt>void</span><span class=w> </span><span class=n>to_json</span><span class=p>(</span><span class=n>BasicJsonType</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>,</span><span class=w> </span><span class=k>const</span><span class=w> </span><span class=n>person</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>)</span>
</span><span class=hll><span class=p>{</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;json_name&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;json_address&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>&quot;json_age&quot;</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"json_name"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"json_address"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=p>;</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>[</span><span class=s>"json_age"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=p>;</span>
</span><span class=hll><span class=p>}</span>
</span><span class=hll>
</span><span class=hll><span class=k>template</span><span class=w> </span><span class=o>&lt;</span><span class=k>typename</span><span class=w> </span><span class=nc>BasicJsonType</span><span class=p>,</span><span class=w> </span><span class=n>nlohmann</span><span class=o>::</span><span class=n>detail</span><span class=o>::</span><span class=n>enable_if_t</span><span class=o>&lt;</span><span class=n>nlohmann</span><span class=o>::</span><span class=n>detail</span><span class=o>::</span><span class=n>is_basic_json</span><span class=o>&lt;</span><span class=n>BasicJsonType</span><span class=o>&gt;::</span><span class=n>value</span><span class=p>,</span><span class=w> </span><span class=kt>int</span><span class=o>&gt;</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=mi>0</span><span class=o>&gt;</span>
</span><span class=hll><span class=kt>void</span><span class=w> </span><span class=n>from_json</span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>BasicJsonType</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>,</span><span class=w> </span><span class=n>person</span><span class=o>&amp;</span><span class=w> </span><span class=n>nlohmann_json_t</span><span class=p>)</span>
</span><span class=hll><span class=p>{</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>at</span><span class=p>(</span><span class=s>&quot;json_name&quot;</span><span class=p>).</span><span class=n>get_to</span><span class=p>(</span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>at</span><span class=p>(</span><span class=s>&quot;json_address&quot;</span><span class=p>).</span><span class=n>get_to</span><span class=p>(</span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=p>);</span>
</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>at</span><span class=p>(</span><span class=s>&quot;json_age&quot;</span><span class=p>).</span><span class=n>get_to</span><span class=p>(</span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>at</span><span class=p>(</span><span class=s>"json_name"</span><span class=p>).</span><span class=n>get_to</span><span class=p>(</span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>name</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>at</span><span class=p>(</span><span class=s>"json_address"</span><span class=p>).</span><span class=n>get_to</span><span class=p>(</span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>address</span><span class=p>);</span>
</span><span class=w> </span><span class=n>nlohmann_json_j</span><span class=p>.</span><span class=n>at</span><span class=p>(</span><span class=s>"json_age"</span><span class=p>).</span><span class=n>get_to</span><span class=p>(</span><span class=n>nlohmann_json_t</span><span class=p>.</span><span class=n>age</span><span class=p>);</span>
<span class=p>}</span>
<span class=p>}</span><span class=w> </span><span class=c1>// namespace ns</span>
<span class=kt>int</span><span class=w> </span><span class=n>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>&quot;Ned Flanders&quot;</span><span class=p>,</span><span class=w> </span><span class=s>&quot;744 Evergreen Terrace&quot;</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=w> </span><span class=n>p</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=s>"Ned Flanders"</span><span class=p>,</span><span class=w> </span><span class=s>"744 Evergreen Terrace"</span><span class=p>,</span><span class=w> </span><span class=mi>60</span><span class=p>};</span>
<span class=w> </span><span class=c1>// serialization: person -&gt; json</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>p</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;serialization: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"serialization: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=c1>// deserialization: json -&gt; person</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;json_address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;json_age&quot;: 40, &quot;json_name&quot;: &quot;Homer Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"json_address": "742 Evergreen Terrace", "json_age": 40, "json_name": "Homer Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p2</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j2</span><span class=p>.</span><span class=k>template</span><span class=w> </span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=c1>// incomplete deserialization:</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>&quot;</span><span class=dl>(</span><span class=s>{&quot;json_address&quot;: &quot;742 Evergreen Terrace&quot;, &quot;json_name&quot;: &quot;Maggie Simpson&quot;}</span><span class=dl>)</span><span class=s>&quot;</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=sa>R</span><span class=s>"</span><span class=dl>(</span><span class=s>{"json_address": "742 Evergreen Terrace", "json_name": "Maggie Simpson"}</span><span class=dl>)</span><span class=s>"</span><span class=n>_json</span><span class=p>;</span>
<span class=w> </span><span class=k>try</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>p3</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j3</span><span class=p>.</span><span class=k>template</span><span class=w> </span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>person</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=p>}</span>
<span class=w> </span><span class=k>catch</span><span class=w> </span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>exception</span><span class=o>&amp;</span><span class=w> </span><span class=n>e</span><span class=p>)</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;deserialization failed: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"deserialization failed: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=p>}</span>
</code></pre></div> </details> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ol> <li>Added in version 3.13.0.</li> </ol> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ol> <li>Added in version 3.13.0.</li> </ol> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 2013-2026 Niels Lohmann </div> </div> <div class=md-social> <a href="https://github.com/nlohmann" target="_blank" rel="noopener" title="github.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 512 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M173.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6m-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3m44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9M252.8 8C114.1 8 8 113.3 8 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C436.2 457.8 504 362.9 504 252 504 113.3 391.5 8 252.8 8M105.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1m-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7m32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1m-11.4-14.7c-1.6 1-1.6 3.6 0 5.9s4.3 3.3 5.6 2.3c1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2"/></svg> </a> <a href="https://www.linkedin.com/in/nielslohmann/" target="_blank" rel="noopener" title="www.linkedin.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 448 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M416 32H31.9C14.3 32 0 46.5 0 64.3v383.4C0 465.5 14.3 480 31.9 480H416c17.6 0 32-14.5 32-32.3V64.3c0-17.8-14.4-32.3-32-32.3M135.4 416H69V202.2h66.5V416zM102.2 96a38.5 38.5 0 1 1 0 77 38.5 38.5 0 1 1 0-77m282.1 320h-66.4V312c0-24.8-.5-56.7-34.5-56.7-34.6 0-39.9 27-39.9 54.9V416h-66.4V202.2h63.7v29.2h.9c8.9-16.8 30.6-34.5 62.9-34.5 67.2 0 79.7 44.3 79.7 101.9z"/></svg> </a> <a href="https://www.xing.com/profile/Niels_Lohmann" target="_blank" rel="noopener" title="www.xing.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 384 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M162.7 210c-1.8 3.3-25.2 44.4-70.1 123.5-4.9 8.3-10.8 12.5-17.7 12.5H9.8c-7.7 0-12.1-7.5-8.5-14.4l69-121.3q.3 0 0-.3l-43.9-75.6c-4.3-7.8Line truncated
@@ -14,4 +14,4 @@
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>QUOTE</span><span class=p>(</span><span class=n>NLOHMANN_JSON_NAMESPACE</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=kc>nl</span><span class=err>ohma</span><span class=kc>nn</span><span class=p>::</span><span class=err>jso</span><span class=kc>n</span><span class=err>_abi_v</span><span class=mi>3</span><span class=err>_</span><span class=mi>12</span><span class=err>_</span><span class=mi>0</span>
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../nlohmann_json_namespace_begin/ ><code>NLOHMANN_JSON_NAMESPACE_BEGIN, NLOHMANN_JSON_NAMESPACE_END</code></a></li> <li><a href=../nlohmann_json_namespace_no_version/ ><code>NLOHMANN_JSON_NAMESPACE_NO_VERSION</code></a></li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.11.0. Changed inline namespace name in version 3.11.2.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 2013-2026 Niels Lohmann </div> </div> <div class=md-social> <a href="https://github.com/nlohmann" target="_blank" rel="noopener" title="github.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 512 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M173.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6m-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3m44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9M252.8 8C114.1 8 8 113.3 8 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C436.2 457.8 504 362.9 504 252 504 113.3 391.5 8 252.8 8M105.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1m-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7m32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1m-11.4-14.7c-1.6 1-1.6 3.6 0 5.9s4.3 3.3 5.6 2.3c1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2"/></svg> </a> <a href="https://www.linkedin.com/in/nielslohmann/" target="_blank" rel="noopener" title="www.linkedin.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 448 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M416 32H31.9C14.3 32 0 46.5 0 64.3v383.4C0 465.5 14.3 480 31.9 480H416c17.6 0 32-14.5 32-32.3V64.3c0-17.8-14.4-32.3-32-32.3M135.4 416H69V202.2h66.5V416zM102.2 96a38.5 38.5 0 1 1 0 77 38.5 38.5 0 1 1 0-77m282.1 320h-66.4V312c0-24.8-.5-56.7-34.5-56.7-34.6 0-39.9 27-39.9 54.9V416h-66.4V202.2h63.7v29.2h.9c8.9-16.8 30.6-34.5 62.9-34.5 67.2 0 79.7 44.3 79.7 101.9z"/></svg> </a> <a href="https://www.xing.com/profile/Niels_Lohmann" target="_blank" rel="noopener" title="www.xing.com" class="md-social__link"> <svg xmlns=http://wwwLine truncated
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../nlohmann_json_namespace_begin/ ><code>NLOHMANN_JSON_NAMESPACE_BEGIN, NLOHMANN_JSON_NAMESPACE_END</code></a></li> <li><a href=../nlohmann_json_namespace_no_version/ ><code>NLOHMANN_JSON_NAMESPACE_NO_VERSION</code></a></li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.11.0. Changed inline namespace name in version 3.11.2.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 2013-2026 Niels Lohmann </div> </div> <div class=md-social> <a href="https://github.com/nlohmann" target="_blank" rel="noopener" title="github.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 512 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M173.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6m-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3m44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9M252.8 8C114.1 8 8 113.3 8 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C436.2 457.8 504 362.9 504 252 504 113.3 391.5 8 252.8 8M105.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1m-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7m32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1m-11.4-14.7c-1.6 1-1.6 3.6 0 5.9s4.3 3.3 5.6 2.3c1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2"/></svg> </a> <a href="https://www.linkedin.com/in/nielslohmann/" target="_blank" rel="noopener" title="www.linkedin.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 448 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M416 32H31.9C14.3 32 0 46.5 0 64.3v383.4C0 465.5 14.3 480 31.9 480H416c17.6 0 32-14.5 32-32.3V64.3c0-17.8-14.4-32.3-32-32.3M135.4 416H69V202.2h66.5V416zM102.2 96a38.5 38.5 0 1 1 0 77 38.5 38.5 0 1 1 0-77m282.1 320h-66.4V312c0-24.8-.5-56.7-34.5-56.7-34.6 0-39.9 27-39.9 54.9V416h-66.4V202.2h63.7v29.2h.9c8.9-16.8 30.6-34.5 62.9-34.5 67.2 0 79.7 44.3 79.7 101.9z"/></svg> </a> <a href="https://www.xing.com/profile/Niels_Lohmann" target="_blank" rel="noopener" title="www.xing.com" class="md-social__link"> <svg xmlns=http://wLine truncated
@@ -40,4 +40,4 @@
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=p>[</span><span class=mi>1</span><span class=p>,</span><span class=kc>null</span><span class=p>]</span>
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../features/namespace/ ><code>nlohmann</code> Namespace</a></li> <li><a href=../nlohmann_json_namespace/ >NLOHMANN_JSON_NAMESPACE</a></li> <li><a href=../nlohmann_json_namespace_no_version/ ><code>NLOHMANN_JSON_NAMESPACE_NO_VERSION</code></a></li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.11.0. Changed inline namespace name in version 3.11.2.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 2013-2026 Niels Lohmann </div> </div> <div class=md-social> <a href="https://github.com/nlohmann" target="_blank" rel="noopener" title="github.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 512 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M173.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6m-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3m44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9M252.8 8C114.1 8 8 113.3 8 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C436.2 457.8 504 362.9 504 252 504 113.3 391.5 8 252.8 8M105.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1m-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7m32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1m-11.4-14.7c-1.6 1-1.6 3.6 0 5.9s4.3 3.3 5.6 2.3c1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2"/></svg> </a> <a href="https://www.linkedin.com/in/nielslohmann/" target="_blank" rel="noopener" title="www.linkedin.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 448 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M416 32H31.9C14.3 32 0 46.5 0 64.3v383.4C0 465.5 14.3 480 31.9 480H416c17.6 0 32-14.5 32-32.3V64.3c0-17.8-14.4-32.3-32-32.3M135.4 416H69V202.2h66.5V416zM102.2 96a38.5 38.5 0 1 1 0 77 38.5 38.5 0 1 1 0-77m282.1 320h-66.4V312c0-24.8-.5-56.7-34.5-56.7-34.6 0-39.9 27-39.9 54.9V416h-66.4V202.2h63.7v29.2h.9c8.9-16.8 30.6-34.5 62.9-34.5 67.2 0 79.7 44.3 79.7 101.9z"/></svg> </a> <a href="https://www.xing.com/profile/Niels_Lohmann" target="_blank" rel="noopener" title="www.xing.com" class="md-social_Line truncated
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../features/namespace/ ><code>nlohmann</code> Namespace</a></li> <li><a href=../nlohmann_json_namespace/ >NLOHMANN_JSON_NAMESPACE</a></li> <li><a href=../nlohmann_json_namespace_no_version/ ><code>NLOHMANN_JSON_NAMESPACE_NO_VERSION</code></a></li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.11.0. Changed inline namespace name in version 3.11.2.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 2013-2026 Niels Lohmann </div> </div> <div class=md-social> <a href="https://github.com/nlohmann" target="_blank" rel="noopener" title="github.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 512 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M173.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6m-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3m44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9M252.8 8C114.1 8 8 113.3 8 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C436.2 457.8 504 362.9 504 252 504 113.3 391.5 8 252.8 8M105.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1m-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7m32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1m-11.4-14.7c-1.6 1-1.6 3.6 0 5.9s4.3 3.3 5.6 2.3c1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2"/></svg> </a> <a href="https://www.linkedin.com/in/nielslohmann/" target="_blank" rel="noopener" title="www.linkedin.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 448 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M416 32H31.9C14.3 32 0 46.5 0 64.3v383.4C0 465.5 14.3 480 31.9 480H416c17.6 0 32-14.5 32-32.3V64.3c0-17.8-14.4-32.3-32-32.3M135.4 416H69V202.2h66.5V416zM102.2 96a38.5 38.5 0 1 1 0 77 38.5 38.5 0 1 1 0-77m282.1 320h-66.4V312c0-24.8-.5-56.7-34.5-56.7-34.6 0-39.9 27-39.9 54.9V416h-66.4V202.2h63.7v29.2h.9c8.9-16.8 30.6-34.5 62.9-34.5 67.2 0 79.7 44.3 79.7 101.9z"/></svg> </a> <a href="https://www.xing.com/profile/Niels_Lohmann" target="_blank" rel="noopener" title="www.xing.com" class="md-sociaLine truncated
@@ -14,4 +14,4 @@
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>QUOTE</span><span class=p>(</span><span class=n>NLOHMANN_JSON_NAMESPACE</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=kc>nl</span><span class=err>ohma</span><span class=kc>nn</span><span class=p>::</span><span class=err>jso</span><span class=kc>n</span><span class=err>_abi</span>
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../features/namespace/ ><code>nlohmann</code> Namespace</a></li> <li><a href=../nlohmann_json_namespace/ ><code>NLOHMANN_JSON_NAMESPACE</code></a></li> <li><a href=../nlohmann_json_namespace_begin/ ><code>NLOHMANN_JSON_NAMESPACE_BEGIN, NLOHMANN_JSON_NAMESPACE_END</code></a></li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.11.2.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../features/namespace/ ><code>nlohmann</code> Namespace</a></li> <li><a href=../nlohmann_json_namespace/ ><code>NLOHMANN_JSON_NAMESPACE</code></a></li> <li><a href=../nlohmann_json_namespace_begin/ ><code>NLOHMANN_JSON_NAMESPACE_BEGIN, NLOHMANN_JSON_NAMESPACE_END</code></a></li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.11.2.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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@@ -21,9 +21,9 @@
<span class=hll><span class=n>NLOHMANN_JSON_SERIALIZE_ENUM</span><span class=p>(</span><span class=n>TaskState</span><span class=p>,</span>
</span><span class=hll><span class=p>{</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>TS_INVALID</span><span class=p>,</span><span class=w> </span><span class=nb>nullptr</span><span class=w> </span><span class=p>},</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>TS_STOPPED</span><span class=p>,</span><span class=w> </span><span class=s>&quot;stopped&quot;</span><span class=w> </span><span class=p>},</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>TS_RUNNING</span><span class=p>,</span><span class=w> </span><span class=s>&quot;running&quot;</span><span class=w> </span><span class=p>},</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>TS_COMPLETED</span><span class=p>,</span><span class=w> </span><span class=s>&quot;completed&quot;</span><span class=w> </span><span class=p>}</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>TS_STOPPED</span><span class=p>,</span><span class=w> </span><span class=s>"stopped"</span><span class=w> </span><span class=p>},</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>TS_RUNNING</span><span class=p>,</span><span class=w> </span><span class=s>"running"</span><span class=w> </span><span class=p>},</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>TS_COMPLETED</span><span class=p>,</span><span class=w> </span><span class=s>"completed"</span><span class=w> </span><span class=p>}</span>
</span><span class=hll><span class=p>})</span>
</span>
<span class=k>enum</span><span class=w> </span><span class=k>class</span><span class=w> </span><span class=nc>Color</span>
@@ -33,8 +33,8 @@
<span class=hll><span class=n>NLOHMANN_JSON_SERIALIZE_ENUM</span><span class=p>(</span><span class=n>Color</span><span class=p>,</span>
</span><span class=hll><span class=p>{</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>unknown</span><span class=p>,</span><span class=w> </span><span class=s>&quot;unknown&quot;</span><span class=w> </span><span class=p>},</span><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>,</span><span class=w> </span><span class=s>&quot;red&quot;</span><span class=w> </span><span class=p>},</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>green</span><span class=p>,</span><span class=w> </span><span class=s>&quot;green&quot;</span><span class=w> </span><span class=p>},</span><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>blue</span><span class=p>,</span><span class=w> </span><span class=s>&quot;blue&quot;</span><span class=w> </span><span class=p>}</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>unknown</span><span class=p>,</span><span class=w> </span><span class=s>"unknown"</span><span class=w> </span><span class=p>},</span><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>,</span><span class=w> </span><span class=s>"red"</span><span class=w> </span><span class=p>},</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>green</span><span class=p>,</span><span class=w> </span><span class=s>"green"</span><span class=w> </span><span class=p>},</span><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>blue</span><span class=p>,</span><span class=w> </span><span class=s>"blue"</span><span class=w> </span><span class=p>}</span>
</span><span class=hll><span class=p>})</span>
</span><span class=p>}</span><span class=w> </span><span class=c1>// namespace ns</span>
@@ -43,27 +43,27 @@
<span class=w> </span><span class=c1>// serialization</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_stopped</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>TS_STOPPED</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_red</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;ns::TS_STOPPED -&gt; &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_stopped</span>
<span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;, ns::Color::red -&gt; &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_red</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"ns::TS_STOPPED -&gt; "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_stopped</span>
<span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>", ns::Color::red -&gt; "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_red</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=c1>// deserialization</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_running</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;running&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_blue</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;blue&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_running</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"running"</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_blue</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"blue"</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>running</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j_running</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>TaskState</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>blue</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j_blue</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>Color</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_running</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot; -&gt; &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>running</span>
<span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;, &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_blue</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot; -&gt; &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=k>static_cast</span><span class=o>&lt;</span><span class=kt>int</span><span class=o>&gt;</span><span class=p>(</span><span class=n>blue</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_running</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>" -&gt; "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>running</span>
<span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>", "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_blue</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>" -&gt; "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=k>static_cast</span><span class=o>&lt;</span><span class=kt>int</span><span class=o>&gt;</span><span class=p>(</span><span class=n>blue</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=c1>// deserializing undefined JSON value to enum</span>
<span class=w> </span><span class=c1>// (where the first map entry above is the default)</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_pi</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=mf>3.14</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>invalid</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j_pi</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>TaskState</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>unknown</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j_pi</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>Color</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_pi</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot; -&gt; &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>invalid</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;, &quot;</span>
<span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_pi</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot; -&gt; &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=k>static_cast</span><span class=o>&lt;</span><span class=kt>int</span><span class=o>&gt;</span><span class=p>(</span><span class=n>unknown</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_pi</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>" -&gt; "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>invalid</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>", "</span>
<span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_pi</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>" -&gt; "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=k>static_cast</span><span class=o>&lt;</span><span class=kt>int</span><span class=o>&gt;</span><span class=p>(</span><span class=n>unknown</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=kc>ns</span><span class=p>::</span><span class=err>TS_STOPPED</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=s2>&quot;stopped&quot;</span><span class=p>,</span><span class=w> </span><span class=kc>ns</span><span class=p>::</span><span class=err>Color</span><span class=p>::</span><span class=err>red</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=s2>&quot;red&quot;</span>
<span class=s2>&quot;running&quot;</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=mi>1</span><span class=p>,</span><span class=w> </span><span class=s2>&quot;blue&quot;</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=mi>2</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=kc>ns</span><span class=p>::</span><span class=err>TS_STOPPED</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=s2>"stopped"</span><span class=p>,</span><span class=w> </span><span class=kc>ns</span><span class=p>::</span><span class=err>Color</span><span class=p>::</span><span class=err>red</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=s2>"red"</span>
<span class=s2>"running"</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=mi>1</span><span class=p>,</span><span class=w> </span><span class=s2>"blue"</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=mi>2</span>
<span class=mf>3.14</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=mi>-1</span><span class=p>,</span><span class=w> </span><span class=mf>3.14</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=mi>3</span>
</code></pre></div> </details> <details class=example> <summary>Example 2: Multiple conversions for one enumerator</summary> <p>The example shows how to use multiple conversions for a single enumerator. In the example, <code>Color::red</code> will always be <em>serialized</em> to <code>"red"</code>, because the first occurring conversion. The second conversion, however, offers an alternative <em>deserialization</em> from <code>"rot"</code> to <code>Color::red</code>.</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
@@ -79,9 +79,9 @@
<span class=n>NLOHMANN_JSON_SERIALIZE_ENUM</span><span class=p>(</span><span class=n>Color</span><span class=p>,</span>
<span class=p>{</span>
<span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>unknown</span><span class=p>,</span><span class=w> </span><span class=s>&quot;unknown&quot;</span><span class=w> </span><span class=p>},</span><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>,</span><span class=w> </span><span class=s>&quot;red&quot;</span><span class=w> </span><span class=p>},</span>
<span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>green</span><span class=p>,</span><span class=w> </span><span class=s>&quot;green&quot;</span><span class=w> </span><span class=p>},</span><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>blue</span><span class=p>,</span><span class=w> </span><span class=s>&quot;blue&quot;</span><span class=w> </span><span class=p>},</span>
<span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>,</span><span class=w> </span><span class=s>&quot;rot&quot;</span><span class=w> </span><span class=p>}</span><span class=w> </span><span class=c1>// a second conversion for Color::red</span>
<span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>unknown</span><span class=p>,</span><span class=w> </span><span class=s>"unknown"</span><span class=w> </span><span class=p>},</span><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>,</span><span class=w> </span><span class=s>"red"</span><span class=w> </span><span class=p>},</span>
<span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>green</span><span class=p>,</span><span class=w> </span><span class=s>"green"</span><span class=w> </span><span class=p>},</span><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>blue</span><span class=p>,</span><span class=w> </span><span class=s>"blue"</span><span class=w> </span><span class=p>},</span>
<span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>,</span><span class=w> </span><span class=s>"rot"</span><span class=w> </span><span class=p>}</span><span class=w> </span><span class=c1>// a second conversion for Color::red</span>
</span><span class=p>})</span>
<span class=p>}</span>
@@ -89,16 +89,16 @@
<span class=p>{</span>
<span class=w> </span><span class=c1>// serialization</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_red</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=k>static_cast</span><span class=o>&lt;</span><span class=kt>int</span><span class=o>&gt;</span><span class=p>(</span><span class=n>ns</span><span class=o>::</span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot; -&gt; &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_red</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=k>static_cast</span><span class=o>&lt;</span><span class=kt>int</span><span class=o>&gt;</span><span class=p>(</span><span class=n>ns</span><span class=o>::</span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>" -&gt; "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_red</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=c1>// deserialization</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_rot</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;rot&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_rot</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"rot"</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>rot</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j_rot</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>Color</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>red</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j_red</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>Color</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_rot</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot; -&gt; &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=k>static_cast</span><span class=o>&lt;</span><span class=kt>int</span><span class=o>&gt;</span><span class=p>(</span><span class=n>rot</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_red</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot; -&gt; &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=k>static_cast</span><span class=o>&lt;</span><span class=kt>int</span><span class=o>&gt;</span><span class=p>(</span><span class=n>red</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_rot</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>" -&gt; "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=k>static_cast</span><span class=o>&lt;</span><span class=kt>int</span><span class=o>&gt;</span><span class=p>(</span><span class=n>rot</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_red</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>" -&gt; "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=k>static_cast</span><span class=o>&lt;</span><span class=kt>int</span><span class=o>&gt;</span><span class=p>(</span><span class=n>red</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=mi>0</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=s2>&quot;red&quot;</span>
<span class=s2>&quot;rot&quot;</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=mi>0</span>
<span class=s2>&quot;red&quot;</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=mi>0</span>
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../features/enum_conversion/ >Specializing enum conversion</a></li> <li><a href=../nlohmann_json_serialize_enum_strict/ ><code>NLOHMANN_JSON_SERIALIZE_ENUM_STRICT</code></a></li> <li><a href=../json_disable_enum_serialization/ ><code>JSON_DISABLE_ENUM_SERIALIZATION</code></a></li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <p>Added in version 3.4.0.</p> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=mi>0</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=s2>"red"</span>
<span class=s2>"rot"</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=mi>0</span>
<span class=s2>"red"</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=mi>0</span>
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../features/enum_conversion/ >Specializing enum conversion</a></li> <li><a href=../nlohmann_json_serialize_enum_strict/ ><code>NLOHMANN_JSON_SERIALIZE_ENUM_STRICT</code></a></li> <li><a href=../json_disable_enum_serialization/ ><code>JSON_DISABLE_ENUM_SERIALIZATION</code></a></li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <p>Added in version 3.4.0.</p> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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@@ -21,9 +21,9 @@
<span class=hll><span class=n>NLOHMANN_JSON_SERIALIZE_ENUM_STRICT</span><span class=p>(</span><span class=n>TaskState</span><span class=p>,</span>
</span><span class=hll><span class=p>{</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>TS_INVALID</span><span class=p>,</span><span class=w> </span><span class=nb>nullptr</span><span class=w> </span><span class=p>},</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>TS_STOPPED</span><span class=p>,</span><span class=w> </span><span class=s>&quot;stopped&quot;</span><span class=w> </span><span class=p>},</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>TS_RUNNING</span><span class=p>,</span><span class=w> </span><span class=s>&quot;running&quot;</span><span class=w> </span><span class=p>},</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>TS_COMPLETED</span><span class=p>,</span><span class=w> </span><span class=s>&quot;completed&quot;</span><span class=w> </span><span class=p>}</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>TS_STOPPED</span><span class=p>,</span><span class=w> </span><span class=s>"stopped"</span><span class=w> </span><span class=p>},</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>TS_RUNNING</span><span class=p>,</span><span class=w> </span><span class=s>"running"</span><span class=w> </span><span class=p>},</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>TS_COMPLETED</span><span class=p>,</span><span class=w> </span><span class=s>"completed"</span><span class=w> </span><span class=p>}</span>
</span><span class=hll><span class=p>})</span>
</span>
<span class=k>enum</span><span class=w> </span><span class=k>class</span><span class=w> </span><span class=nc>Color</span>
@@ -33,8 +33,8 @@
<span class=hll><span class=n>NLOHMANN_JSON_SERIALIZE_ENUM_STRICT</span><span class=p>(</span><span class=n>Color</span><span class=p>,</span>
</span><span class=hll><span class=p>{</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>unknown</span><span class=p>,</span><span class=w> </span><span class=s>&quot;unknown&quot;</span><span class=w> </span><span class=p>},</span><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>,</span><span class=w> </span><span class=s>&quot;red&quot;</span><span class=w> </span><span class=p>},</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>green</span><span class=p>,</span><span class=w> </span><span class=s>&quot;green&quot;</span><span class=w> </span><span class=p>},</span><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>blue</span><span class=p>,</span><span class=w> </span><span class=s>&quot;blue&quot;</span><span class=w> </span><span class=p>}</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>unknown</span><span class=p>,</span><span class=w> </span><span class=s>"unknown"</span><span class=w> </span><span class=p>},</span><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>,</span><span class=w> </span><span class=s>"red"</span><span class=w> </span><span class=p>},</span>
</span><span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>green</span><span class=p>,</span><span class=w> </span><span class=s>"green"</span><span class=w> </span><span class=p>},</span><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>blue</span><span class=p>,</span><span class=w> </span><span class=s>"blue"</span><span class=w> </span><span class=p>}</span>
</span><span class=hll><span class=p>})</span>
</span><span class=p>}</span><span class=w> </span><span class=c1>// namespace ns</span>
@@ -43,20 +43,20 @@
<span class=w> </span><span class=c1>// serialization</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_stopped</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>TS_STOPPED</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_red</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;ns::TS_STOPPED -&gt; &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_stopped</span>
<span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;, ns::Color::red -&gt; &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_red</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"ns::TS_STOPPED -&gt; "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_stopped</span>
<span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>", ns::Color::red -&gt; "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_red</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=c1>// deserialization</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_running</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;running&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_blue</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;blue&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_running</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"running"</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_blue</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"blue"</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>running</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j_running</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>TaskState</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>blue</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j_blue</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>Color</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_running</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot; -&gt; &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>running</span>
<span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;, &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_blue</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot; -&gt; &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=k>static_cast</span><span class=o>&lt;</span><span class=kt>int</span><span class=o>&gt;</span><span class=p>(</span><span class=n>blue</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_running</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>" -&gt; "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>running</span>
<span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>", "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_blue</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>" -&gt; "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=k>static_cast</span><span class=o>&lt;</span><span class=kt>int</span><span class=o>&gt;</span><span class=p>(</span><span class=n>blue</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=kc>ns</span><span class=p>::</span><span class=err>TS_STOPPED</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=s2>&quot;stopped&quot;</span><span class=p>,</span><span class=w> </span><span class=kc>ns</span><span class=p>::</span><span class=err>Color</span><span class=p>::</span><span class=err>red</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=s2>&quot;red&quot;</span>
<span class=s2>&quot;running&quot;</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=mi>1</span><span class=p>,</span><span class=w> </span><span class=s2>&quot;blue&quot;</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=mi>2</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=kc>ns</span><span class=p>::</span><span class=err>TS_STOPPED</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=s2>"stopped"</span><span class=p>,</span><span class=w> </span><span class=kc>ns</span><span class=p>::</span><span class=err>Color</span><span class=p>::</span><span class=err>red</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=s2>"red"</span>
<span class=s2>"running"</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=mi>1</span><span class=p>,</span><span class=w> </span><span class=s2>"blue"</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=mi>2</span>
</code></pre></div> </details> <details class=example> <summary>Example 2: Multiple conversions for one enumerator</summary> <p>The example shows how to use multiple conversions for a single enumerator. In the example, <code>Color::red</code> will always be <em>serialized</em> to <code>"red"</code>, because the first occurring conversion. The second conversion, however, offers an alternative <em>deserialization</em> from <code>"rot"</code> to <code>Color::red</code>.</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
@@ -71,9 +71,9 @@
<span class=n>NLOHMANN_JSON_SERIALIZE_ENUM_STRICT</span><span class=p>(</span><span class=n>Color</span><span class=p>,</span>
<span class=p>{</span>
<span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>unknown</span><span class=p>,</span><span class=w> </span><span class=s>&quot;unknown&quot;</span><span class=w> </span><span class=p>},</span><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>,</span><span class=w> </span><span class=s>&quot;red&quot;</span><span class=w> </span><span class=p>},</span>
<span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>green</span><span class=p>,</span><span class=w> </span><span class=s>&quot;green&quot;</span><span class=w> </span><span class=p>},</span><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>blue</span><span class=p>,</span><span class=w> </span><span class=s>&quot;blue&quot;</span><span class=w> </span><span class=p>},</span>
<span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>,</span><span class=w> </span><span class=s>&quot;rot&quot;</span><span class=w> </span><span class=p>}</span><span class=w> </span><span class=c1>// a second conversion for Color::red</span>
<span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>unknown</span><span class=p>,</span><span class=w> </span><span class=s>"unknown"</span><span class=w> </span><span class=p>},</span><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>,</span><span class=w> </span><span class=s>"red"</span><span class=w> </span><span class=p>},</span>
<span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>green</span><span class=p>,</span><span class=w> </span><span class=s>"green"</span><span class=w> </span><span class=p>},</span><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>blue</span><span class=p>,</span><span class=w> </span><span class=s>"blue"</span><span class=w> </span><span class=p>},</span>
<span class=hll><span class=w> </span><span class=p>{</span><span class=w> </span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>,</span><span class=w> </span><span class=s>"rot"</span><span class=w> </span><span class=p>}</span><span class=w> </span><span class=c1>// a second conversion for Color::red</span>
</span><span class=p>})</span>
<span class=p>}</span>
@@ -81,18 +81,18 @@
<span class=p>{</span>
<span class=w> </span><span class=c1>// serialization</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_red</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=k>static_cast</span><span class=o>&lt;</span><span class=kt>int</span><span class=o>&gt;</span><span class=p>(</span><span class=n>ns</span><span class=o>::</span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot; -&gt; &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_red</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=k>static_cast</span><span class=o>&lt;</span><span class=kt>int</span><span class=o>&gt;</span><span class=p>(</span><span class=n>ns</span><span class=o>::</span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>" -&gt; "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_red</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=c1>// deserialization</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_rot</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>&quot;rot&quot;</span><span class=p>;</span>
<span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>j_rot</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"rot"</span><span class=p>;</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>rot</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j_rot</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>Color</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=k>auto</span><span class=w> </span><span class=n>red</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>j_red</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>Color</span><span class=o>&gt;</span><span class=p>();</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_rot</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot; -&gt; &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=k>static_cast</span><span class=o>&lt;</span><span class=kt>int</span><span class=o>&gt;</span><span class=p>(</span><span class=n>rot</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_red</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot; -&gt; &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=k>static_cast</span><span class=o>&lt;</span><span class=kt>int</span><span class=o>&gt;</span><span class=p>(</span><span class=n>red</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_rot</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>" -&gt; "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=k>static_cast</span><span class=o>&lt;</span><span class=kt>int</span><span class=o>&gt;</span><span class=p>(</span><span class=n>rot</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>j_red</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>" -&gt; "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=k>static_cast</span><span class=o>&lt;</span><span class=kt>int</span><span class=o>&gt;</span><span class=p>(</span><span class=n>red</span><span class=p>)</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=mi>0</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=s2>&quot;red&quot;</span>
<span class=s2>&quot;rot&quot;</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=mi>0</span>
<span class=s2>&quot;red&quot;</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=mi>0</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=mi>0</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=s2>"red"</span>
<span class=s2>"rot"</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=mi>0</span>
<span class=s2>"red"</span><span class=w> </span><span class=mi>-</span><span class=err>&gt;</span><span class=w> </span><span class=mi>0</span>
</code></pre></div> </details> <details class=example> <summary>Example 3: exceptions on invalid serialization</summary> <p>The example shows how an invalid serialization causes an exception to be thrown. In the example, Color::unknown is not defined in the mapping used to call <code>NLOHMANN_JSON_SERIALIZE_ENUM_STRICT</code> so causes an exception when used to serialize. Similarly, "what" does not refer to an enum value so also causes an exception when deserialization is attempted.</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
@@ -111,9 +111,9 @@
<span class=n>NLOHMANN_JSON_SERIALIZE_ENUM_STRICT</span><span class=p>(</span><span class=n>Color</span><span class=p>,</span>
<span class=p>{</span>
<span class=w> </span><span class=p>{</span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>,</span><span class=w> </span><span class=s>&quot;red&quot;</span><span class=p>},</span>
<span class=w> </span><span class=p>{</span><span class=n>Color</span><span class=o>::</span><span class=n>green</span><span class=p>,</span><span class=w> </span><span class=s>&quot;green&quot;</span><span class=p>},</span>
<span class=w> </span><span class=p>{</span><span class=n>Color</span><span class=o>::</span><span class=n>blue</span><span class=p>,</span><span class=w> </span><span class=s>&quot;blue&quot;</span><span class=p>}</span>
<span class=w> </span><span class=p>{</span><span class=n>Color</span><span class=o>::</span><span class=n>red</span><span class=p>,</span><span class=w> </span><span class=s>"red"</span><span class=p>},</span>
<span class=w> </span><span class=p>{</span><span class=n>Color</span><span class=o>::</span><span class=n>green</span><span class=p>,</span><span class=w> </span><span class=s>"green"</span><span class=p>},</span>
<span class=w> </span><span class=p>{</span><span class=n>Color</span><span class=o>::</span><span class=n>blue</span><span class=p>,</span><span class=w> </span><span class=s>"blue"</span><span class=p>}</span>
<span class=p>})</span>
<span class=p>}</span><span class=w> </span><span class=c1>// namespace ns</span>
@@ -129,23 +129,23 @@
</span><span class=w> </span><span class=p>}</span>
<span class=w> </span><span class=k>catch</span><span class=w> </span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>exception</span><span class=w> </span><span class=n>e</span><span class=p>)</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;deserialization failed: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"deserialization failed: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=w> </span><span class=c1>// invalid deserialization</span>
<span class=w> </span><span class=k>try</span>
<span class=w> </span><span class=p>{</span>
<span class=hll><span class=w> </span><span class=c1>// what does not map to an enum</span>
</span><span class=hll><span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>invalid_deserialization</span><span class=p>(</span><span class=s>&quot;what&quot;</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>json</span><span class=w> </span><span class=n>invalid_deserialization</span><span class=p>(</span><span class=s>"what"</span><span class=p>);</span>
</span><span class=hll><span class=w> </span><span class=n>ns</span><span class=o>::</span><span class=n>Color</span><span class=w> </span><span class=n>color</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>invalid_deserialization</span><span class=p>.</span><span class=n>get</span><span class=o>&lt;</span><span class=n>ns</span><span class=o>::</span><span class=n>Color</span><span class=o>&gt;</span><span class=p>();</span>
</span><span class=w> </span><span class=p>}</span>
<span class=w> </span><span class=k>catch</span><span class=w> </span><span class=p>(</span><span class=k>const</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>exception</span><span class=w> </span><span class=n>e</span><span class=p>)</span>
<span class=w> </span><span class=p>{</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;deserialization failed: &quot;</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"deserialization failed: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>e</span><span class=p>.</span><span class=n>what</span><span class=p>()</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=w> </span><span class=p>}</span>
<span class=w> </span><span class=k>return</span><span class=w> </span><span class=mi>0</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> <p>Output: <div class=highlight><pre><span></span><code><span class=err>deserializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=w> </span><span class=kc>fa</span><span class=err>iled</span><span class=p>:</span><span class=w> </span><span class=p>[</span><span class=err>jso</span><span class=kc>n</span><span class=err>.excep</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=err>.ou</span><span class=kc>t</span><span class=err>_o</span><span class=kc>f</span><span class=err>_ra</span><span class=kc>n</span><span class=err>ge.</span><span class=mi>410</span><span class=p>]</span><span class=w> </span><span class=err>e</span><span class=kc>nu</span><span class=err>m</span><span class=w> </span><span class=err>value</span><span class=w> </span><span class=err>ou</span><span class=kc>t</span><span class=w> </span><span class=err>o</span><span class=kc>f</span><span class=w> </span><span class=err>ra</span><span class=kc>n</span><span class=err>ge</span><span class=w> </span><span class=kc>f</span><span class=err>or</span><span class=w> </span><span class=err>Color</span>
<span class=err>deserializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=w> </span><span class=kc>fa</span><span class=err>iled</span><span class=p>:</span><span class=w> </span><span class=p>[</span><span class=err>jso</span><span class=kc>n</span><span class=err>.excep</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=err>.ou</span><span class=kc>t</span><span class=err>_o</span><span class=kc>f</span><span class=err>_ra</span><span class=kc>n</span><span class=err>ge.</span><span class=mi>410</span><span class=p>]</span><span class=w> </span><span class=err>e</span><span class=kc>nu</span><span class=err>m</span><span class=w> </span><span class=err>value</span><span class=w> </span><span class=err>ou</span><span class=kc>t</span><span class=w> </span><span class=err>o</span><span class=kc>f</span><span class=w> </span><span class=err>ra</span><span class=kc>n</span><span class=err>ge</span><span class=w> </span><span class=kc>f</span><span class=err>or</span><span class=w> </span><span class=err>Color</span><span class=p>:</span><span class=w> </span><span class=s2>&quot;what&quot;</span>
</code></pre></div></p> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../features/enum_conversion/ >Specializing enum conversion</a></li> <li><a href=../nlohmann_json_serialize_enum/ ><code>NLOHMANN_JSON_SERIALIZE_ENUM</code></a></li> <li><a href=../json_disable_enum_serialization/ ><code>JSON_DISABLE_ENUM_SERIALIZATION</code></a></li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <p>Added in version 3.13.0.</p> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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<span class=err>deserializa</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=w> </span><span class=kc>fa</span><span class=err>iled</span><span class=p>:</span><span class=w> </span><span class=p>[</span><span class=err>jso</span><span class=kc>n</span><span class=err>.excep</span><span class=kc>t</span><span class=err>io</span><span class=kc>n</span><span class=err>.ou</span><span class=kc>t</span><span class=err>_o</span><span class=kc>f</span><span class=err>_ra</span><span class=kc>n</span><span class=err>ge.</span><span class=mi>410</span><span class=p>]</span><span class=w> </span><span class=err>e</span><span class=kc>nu</span><span class=err>m</span><span class=w> </span><span class=err>value</span><span class=w> </span><span class=err>ou</span><span class=kc>t</span><span class=w> </span><span class=err>o</span><span class=kc>f</span><span class=w> </span><span class=err>ra</span><span class=kc>n</span><span class=err>ge</span><span class=w> </span><span class=kc>f</span><span class=err>or</span><span class=w> </span><span class=err>Color</span><span class=p>:</span><span class=w> </span><span class=s2>"what"</span>
</code></pre></div></p> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../../features/enum_conversion/ >Specializing enum conversion</a></li> <li><a href=../nlohmann_json_serialize_enum/ ><code>NLOHMANN_JSON_SERIALIZE_ENUM</code></a></li> <li><a href=../json_disable_enum_serialization/ ><code>JSON_DISABLE_ENUM_SERIALIZATION</code></a></li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <p>Added in version 3.13.0.</p> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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@@ -8,10 +8,10 @@
<span class=kt>int</span><span class=w> </span><span class=nf>main</span><span class=p>()</span>
<span class=p>{</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;JSON for Modern C++ version &quot;</span>
<span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>NLOHMANN_JSON_VERSION_MAJOR</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;.&quot;</span>
<span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>NLOHMANN_JSON_VERSION_MINOR</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>&quot;.&quot;</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cout</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"JSON for Modern C++ version "</span>
<span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>NLOHMANN_JSON_VERSION_MAJOR</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"."</span>
<span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>NLOHMANN_JSON_VERSION_MINOR</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"."</span>
<span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>NLOHMANN_JSON_VERSION_PATCH</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>endl</span><span class=p>;</span>
<span class=p>}</span>
</code></pre></div> <p>Output:</p> <div class=highlight><pre><span></span><code><span class=err>JSON</span><span class=w> </span><span class=kc>f</span><span class=err>or</span><span class=w> </span><span class=err>Moder</span><span class=kc>n</span><span class=w> </span><span class=err>C++</span><span class=w> </span><span class=err>versio</span><span class=kc>n</span><span class=w> </span><span class=mf>3.12.0</span>
</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../basic_json/meta/ >meta</a> - returns version information on the library</li> <li><a href=../json_skip_library_version_check/ >JSON_SKIP_LIBRARY_VERSION_CHECK</a> - skip library version check</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.1.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 7, 2026 17:29:58 UTC">August 7, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../../basic_json/meta/ >meta</a> - returns version information on the library</li> <li><a href=../json_skip_library_version_check/ >JSON_SKIP_LIBRARY_VERSION_CHECK</a> - skip library version check</li> </ul> <h2 id=version-history>Version history<a class=headerlink href=#version-history title="Permanent link">&para;</a></h2> <ul> <li>Added in version 3.1.0.</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="August 19, 2026 18:19:47 UTC">August 19, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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