Niels Lohmann
a47170346a
* docs: new design for the documentation site Apply the brand to the Material for MkDocs site: Inter and JetBrains Mono served by the site (upright and real italic), brand colours, blue header band with the syntax pattern, wordmark in the header, new home page (hero, cards, animated feature tour), 404 page, polish for tabs, search, footer, focus rings, tables and code blocks, and theme features (code copy, previous/next footer, TOC follow, search suggestions). Draw the number railroad diagram, the parser callback events and the iterator illustrations as inline SVGs that follow the light and dark scheme. The generator scripts are in docs/mkdocs/scripts/figures; the feature slideshow (json-light.svg, json-dark.svg, replacing json.gif on the home page) is built by docs/mkdocs/scripts/slideshow. Decision nodes in five flowcharts become hexagons, which need far less room. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * docs: add figures, table captions and a macro chooser - Figures with numbered captions: SAX stepper, json_view layout and edit stepper, exception map, JSON pointer and patch walkers, QA pipeline, scaling and binary size charts, roadmap lanes, release timeline, integration decision tree and namespace builder - Table captions (nj-table-caption) on 9 pages - Compile times: modules and PCH charts, filesystem section, re-measured Figure 1, links between features/modules.md and compile_times.md - Interactive macro chooser for features/arbitrary_types.md - Link check: exclude URLs that answer the plugin with 400/401/419 or are dead (customers.md) Signed-off-by: Niels Lohmann <mail@nlohmann.me> * docs: macro chooser generates adl_serializer for non-default-constructible types Signed-off-by: Niels Lohmann <mail@nlohmann.me> * docs: cross-link concept pages and API pages in See also sections Add See also links in both directions between the concept pages (features, home, integration) and the API pages, write API links in code font, give every entry a comment after a dash, and show the callback event figure on the parser callbacks page. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * docs: address review comments on the new design - Home: add a "Latest release" button - Sponsors: update the list and group it by tier - Features: list all feature pages on the index page - Releases: add highlights per release, link the 4.0 roadmap, add the first commit to the timeline - Exceptions: prefix all example messages with the exception name - API: no code font for format names in the See also links of the to_/from_ pages - Merge Patch: show the document before, the patch, and the result - Replace "--" with typographic dashes, mark external links with an icon, center Mermaid diagrams Signed-off-by: Niels Lohmann <mail@nlohmann.me> --------- Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2.1 KiB
2.1 KiB
JSON_ASSERT
#define JSON_ASSERT(x) /* value */
This macro controls which code is executed for runtime assertions of the library.
Parameters
x(in)- expression of a scalar type
Default definition
The default value is #!cpp assert(x).
#define JSON_ASSERT(x) assert(x)
Therefore, assertions can be switched off by defining NDEBUG.
Notes
- The library uses numerous assertions to guarantee invariants and to abort in case of otherwise undefined behavior
(e.g., when calling operator[] with a missing object key on a
constobject). See page runtime assertions for more information. - Defining the macro to code that does not call
std::abortmay leave the library in an undefined state. - The macro is undefined outside the library.
Examples
??? example "Example: default behavior"
The following code will trigger an assertion at runtime:
```cpp
#include <nlohmann/json.hpp>
using nlohmann::json;
int main()
{
const json j = {{"key", "value"}};
auto v = j["missing"];
}
```
Output:
```
Assertion failed: (m_value.object->find(key) != m_value.object->end()), function operator[], file json.hpp, line 2144.
```
??? example "Example: user-defined behavior"
The assertion reporting can be changed by defining `JSON_ASSERT(x)` differently.
```cpp
#include <cstdio>
#include <cstdlib>
#define JSON_ASSERT(x) if(!(x)){fprintf(stderr, "assertion error in %s\n", __FUNCTION__); std::abort();}
#include <nlohmann/json.hpp>
using nlohmann::json;
int main()
{
const json j = {{"key", "value"}};
auto v = j["missing"];
}
```
Output:
```
assertion error in operator[]
```
See also
- Runtime Assertions - overview documentation
- Supported Macros - guide to all supported macros
Version history
- Added in version 3.9.0.