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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/features/parsing/parse_exceptions/" rel="canonical"><link href=../json_lines/ rel=prev><link href=../parser_callbacks/ rel=next><link rel=icon href=../../../assets/images/favicon.png><meta name=generator content="mkdocs-1.6.1, mkdocs-material-9.7.7"><title>Parsing and Exceptions - 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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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> </form> <script>var palette=__md_get("__palette");if(palette&&palette.color){if("(prefers-color-scheme)"===palette.color.media){var media=matchMedia("(prefers-color-scheme: light)"),input=document.querySelector(media.matches?"[data-md-color-media='(prefers-color-scheme: light)']":"[data-md-color-media='(prefers-color-scheme: dark)']");palette.color.media=input.getAttribute("data-md-color-media"),palette.color.scheme=input.getAttribute("data-md-color-scheme"),palette.color.primary=input.getAttribute("data-md-color-primary"),palette.color.accent=input.getAttribute("data-md-color-accent")}for(var[key,value]of Object.entries(palette.color))document.body.setAttribute("data-md-color-"+key,value)}</script> <label class="md-header__button md-icon" for=__search> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M9.5 3A6.5 6.5 0 0 1 16 9.5c0 1.61-.59 3.09-1.56 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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/features/parsing/parse_exceptions/" rel="canonical"><link href=../json_lines/ rel=prev><link href=../parser_callbacks/ rel=next><link rel=icon href=../../../assets/images/favicon.png><meta name=generator content="mkdocs-1.6.1, mkdocs-material-9.7.7"><title>Parsing and Exceptions - 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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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> Parsing and Exceptions </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 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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> </form> <script>var palette=__md_get("__palette");if(palette&&palette.color){if("(prefers-color-scheme)"===palette.color.media){var media=matchMedia("(prefers-color-scheme: light)"),input=document.querySelector(media.matches?"[data-md-color-media='(prefers-color-scheme: light)']":"[data-md-color-media='(prefers-color-scheme: dark)']");palette.color.media=input.getAttribute("data-md-color-media"),palette.color.scheme=input.getAttribute("data-md-color-scheme"),palette.color.primary=input.getAttribute("data-md-color-primary"),palette.color.accent=input.getAttribute("data-md-color-accent")}for(var[key,value]of Object.entries(palette.color))document.body.setAttribute("data-md-color-"+key,value)}</script> <label class="md-header__button md-icon" for=__search> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M9.5 3A6.5 6.5 0 0 1 16 9.5c0 1.61-.59 3.09-1.56 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<span class=k>try</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=n>json</span><span class=o>::</span><span class=n>parse</span><span class=p>(</span><span class=n>my_input</span><span class=p>);</span>
@@ -7,35 +7,36 @@
<span class=p>{</span>
<span class=w> </span><span class=n>std</span><span class=o>::</span><span class=n>cerr</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"parse error at byte "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>ex</span><span class=p>.</span><span class=kt>byte</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>In case exceptions are undesired or not supported by the environment, there are different ways to proceed:</p> <h2 id=switch-off-exceptions>Switch off exceptions<a class=headerlink href=#switch-off-exceptions title="Permanent link">&para;</a></h2> <p>The <code>parse()</code> function accepts a <code class=highlight><span class=kt>bool</span></code> parameter <code>allow_exceptions</code> which controls whether an exception is thrown when a parse error occurs (<code class=highlight><span class=nb>true</span></code>, default) or whether a discarded value should be returned (<code class=highlight><span class=nb>false</span></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>parse</span><span class=p>(</span><span class=n>my_input</span><span class=p>,</span><span class=w> </span><span class=nb>nullptr</span><span class=p>,</span><span class=w> </span><span class=nb>false</span><span class=p>);</span>
</code></pre></div> <p>In case exceptions are undesired or not supported by the environment, there are different ways to proceed:</p> <h2 id=switch-off-exceptions>Switch off exceptions<a class=headerlink href=#switch-off-exceptions title="Permanent link">&para;</a></h2> <p>The <a href=../../../api/basic_json/parse/ ><code>parse()</code></a> function accepts a <code class=highlight><span class=kt>bool</span></code> parameter <code>allow_exceptions</code> which controls whether an exception is thrown when a parse error occurs (<code class=highlight><span class=nb>true</span></code>, default) or whether a discarded value should be returned (<code class=highlight><span class=nb>false</span></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>parse</span><span class=p>(</span><span class=n>my_input</span><span class=p>,</span><span class=w> </span><span class=nb>nullptr</span><span class=p>,</span><span class=w> </span><span class=nb>false</span><span class=p>);</span>
<span class=k>if</span><span class=w> </span><span class=p>(</span><span class=n>j</span><span class=p>.</span><span class=n>is_discarded</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>cerr</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"parse error"</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 there is no diagnostic information available in this scenario.</p> <h2 id=use-accept-function>Use accept() function<a class=headerlink href=#use-accept-function title="Permanent link">&para;</a></h2> <p>Alternatively, function <code>accept()</code> can be used which does not return a <code>json</code> value, but a <code class=highlight><span class=kt>bool</span></code> indicating whether the input is valid <abbr title="JavaScript Object Notation">JSON</abbr>.</p> <div class=highlight><pre><span></span><code><span class=k>if</span><span class=w> </span><span class=p>(</span><span class=o>!</span><span class=n>json</span><span class=o>::</span><span class=n>accept</span><span class=p>(</span><span class=n>my_input</span><span class=p>))</span>
</code></pre></div> <p>Note there is no diagnostic information available in this scenario.</p> <h2 id=use-accept-function>Use accept() function<a class=headerlink href=#use-accept-function title="Permanent link">&para;</a></h2> <p>Alternatively, function <a href=../../../api/basic_json/accept/ ><code>accept()</code></a> can be used which does not return a <code>json</code> value, but a <code class=highlight><span class=kt>bool</span></code> indicating whether the input is valid <abbr title="JavaScript Object Notation">JSON</abbr>.</p> <div class=highlight><pre><span></span><code><span class=k>if</span><span class=w> </span><span class=p>(</span><span class=o>!</span><span class=n>json</span><span class=o>::</span><span class=n>accept</span><span class=p>(</span><span class=n>my_input</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>cerr</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"parse error"</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>Again, there is no diagnostic information available.</p> <h2 id=user-defined-sax-interface>User-defined <abbr title="Simple API for XML">SAX</abbr> interface<a class=headerlink href=#user-defined-sax-interface title="Permanent link">&para;</a></h2> <p>Finally, you can implement the <a href=../sax_interface/ ><abbr title="Simple API for XML">SAX</abbr> interface</a> and decide what should happen in case of a parse error.</p> <p>This function has the following interface:</p> <div class=highlight><pre><span></span><code><span class=kt>bool</span><span class=w> </span><span class=nf>parse_error</span><span class=p>(</span><span class=n>std</span><span class=o>::</span><span class=kt>size_t</span><span class=w> </span><span class=n>position</span><span class=p>,</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=o>&amp;</span><span class=w> </span><span class=n>last_token</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=o>::</span><span class=n>exception</span><span class=o>&amp;</span><span class=w> </span><span class=n>ex</span><span class=p>);</span>
</code></pre></div> <p>The return value indicates whether the parsing should continue, so the function should usually return <code class=highlight><span class=nb>false</span></code>.</p> <details class=example> <summary>Example</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>The return value indicates whether the parsing should continue, so the function should usually return <code class=highlight><span class=nb>false</span></code>.</p> <details class=example> <summary>Example: report parse errors without exceptions</summary> <p>The example derives from the library's <abbr title="Document Object Model">DOM</abbr> parser and overrides <code>parse_error</code> to print the error instead of throwing. Note the <abbr title="Document Object Model">DOM</abbr> parser is an implementation detail (<code>nlohmann::detail</code>) and may change between releases; see <a href=../../../integration/migration_guide/#do-not-use-the-detail-namespace>Do not use the <code>detail</code> namespace</a>.</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>
<span class=k>using</span><span class=w> </span><span class=n>json</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann</span><span class=o>::</span><span class=n>json</span><span class=p>;</span>
<span class=k>class</span><span class=w> </span><span class=nc>sax_no_exception</span><span class=w> </span><span class=o>:</span><span class=w> </span><span class=k>public</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>json_sax_dom_parser</span><span class=o>&lt;</span><span class=n>json</span><span class=o>&gt;</span>
<span class=c1>// a DOM parser that reports parse errors instead of throwing</span>
<span class=k>class</span><span class=w> </span><span class=nc>sax_no_exception</span><span class=w> </span><span class=o>:</span><span class=w> </span><span class=k>public</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>json_sax_dom_parser</span><span class=o>&lt;</span><span class=n>json</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>string_input_adapter_type</span><span class=o>&gt;</span>
<span class=p>{</span>
<span class=w> </span><span class=k>public</span><span class=o>:</span>
<span class=w> </span><span class=n>sax_no_exception</span><span class=p>(</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=o>:</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>json_sax_dom_parser</span><span class=o>&lt;</span><span class=n>json</span><span class=o>&gt;</span><span class=p>(</span><span class=n>j</span><span class=p>,</span><span class=w> </span><span class=nb>false</span><span class=p>)</span>
<span class=w> </span><span class=k>explicit</span><span class=w> </span><span class=n>sax_no_exception</span><span class=p>(</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=o>:</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>json_sax_dom_parser</span><span class=o>&lt;</span><span class=n>json</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>string_input_adapter_type</span><span class=o>&gt;</span><span class=p>(</span><span class=n>j</span><span class=p>,</span><span class=w> </span><span class=nb>false</span><span class=p>)</span>
<span class=w> </span><span class=p>{}</span>
<span class=w> </span><span class=kt>bool</span><span class=w> </span><span class=n>parse_error</span><span class=p>(</span><span class=n>std</span><span class=o>::</span><span class=kt>size_t</span><span class=w> </span><span class=n>position</span><span class=p>,</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=o>&amp;</span><span class=w> </span><span class=n>last_token</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=o>::</span><span class=n>exception</span><span class=o>&amp;</span><span class=w> </span><span class=n>ex</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>cerr</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"parse error at input byte "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>position</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=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>"parse error at input byte "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>position</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=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>ex</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=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>"last read: </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=n>last_token</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>"</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>
@@ -53,7 +54,7 @@
<span class=w> </span><span class=kt>bool</span><span class=w> </span><span class=n>parse_result</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>sax_parse</span><span class=p>(</span><span class=n>myinput</span><span class=p>,</span><span class=w> </span><span class=o>&amp;</span><span class=n>sax</span><span class=p>);</span>
<span class=w> </span><span class=k>if</span><span class=w> </span><span class=p>(</span><span class=o>!</span><span class=n>parse_result</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>cerr</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=s>"parsing unsuccessful!"</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>"parsing unsuccessful!"</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=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 value: "</span><span class=w> </span><span class=o>&lt;&lt;</span><span class=w> </span><span class=n>result</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>
@@ -63,4 +64,4 @@
last read: "3,]"
parsing unsuccessful!
parsed value: [1,2,3]
</code></pre></div> </details> <!-- 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="October 2, 2026 09:23:55 UTC">October 2, 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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+11 -8
View File
@@ -18,7 +18,7 @@ In case exceptions are undesired or not supported by the environment, there are
## Switch off exceptions
The `parse()` function accepts a `bool` parameter `allow_exceptions` which controls whether an exception is thrown when a parse error occurs (`true`, default) or whether a discarded value should be returned (`false`).
The [`parse()`](https://json.nlohmann.me/api/basic_json/parse/index.md) function accepts a `bool` parameter `allow_exceptions` which controls whether an exception is thrown when a parse error occurs (`true`, default) or whether a discarded value should be returned (`false`).
```
json j = json::parse(my_input, nullptr, false);
@@ -32,7 +32,7 @@ Note there is no diagnostic information available in this scenario.
## Use accept() function
Alternatively, function `accept()` can be used which does not return a `json` value, but a `bool` indicating whether the input is valid JSON.
Alternatively, function [`accept()`](https://json.nlohmann.me/api/basic_json/accept/index.md) can be used which does not return a `json` value, but a `bool` indicating whether the input is valid JSON.
```
if (!json::accept(my_input))
@@ -57,7 +57,9 @@ bool parse_error(std::size_t position,
The return value indicates whether the parsing should continue, so the function should usually return `false`.
Example
Example: report parse errors without exceptions
The example derives from the library's DOM parser and overrides `parse_error` to print the error instead of throwing. Note the DOM parser is an implementation detail (`nlohmann::detail`) and may change between releases; see [Do not use the `detail` namespace](https://json.nlohmann.me/integration/migration_guide/#do-not-use-the-detail-namespace).
```
#include <iostream>
@@ -65,18 +67,19 @@ Example
using json = nlohmann::json;
class sax_no_exception : public nlohmann::detail::json_sax_dom_parser<json>
// a DOM parser that reports parse errors instead of throwing
class sax_no_exception : public nlohmann::detail::json_sax_dom_parser<json, nlohmann::detail::string_input_adapter_type>
{
public:
sax_no_exception(json& j)
: nlohmann::detail::json_sax_dom_parser<json>(j, false)
explicit sax_no_exception(json& j)
: nlohmann::detail::json_sax_dom_parser<json, nlohmann::detail::string_input_adapter_type>(j, false)
{}
bool parse_error(std::size_t position,
const std::string& last_token,
const json::exception& ex)
{
std::cerr << "parse error at input byte " << position << "\n"
std::cout << "parse error at input byte " << position << "\n"
<< ex.what() << "\n"
<< "last read: \"" << last_token << "\""
<< std::endl;
@@ -94,7 +97,7 @@ int main()
bool parse_result = json::sax_parse(myinput, &sax);
if (!parse_result)
{
std::cerr << "parsing unsuccessful!" << std::endl;
std::cout << "parsing unsuccessful!" << std::endl;
}
std::cout << "parsed value: " << result << std::endl;