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* mkdocs: add string_view examples * mkdocs: reference underlying operators * mkdocs: add operator<=> examples * mkdocs: fix style check issues * mkdocs: tweak BJData page * mkdocs: add CMake option hints to macros * mkdocs: fix JSON_DISABLE_ENUM_SERIALIZATION definition * mkdocs: fix link to unit-udt.cpp * mkdocs: fix "Arbitrary Type Conversions" title * mkdocs: link to api/macros/*.md instead of features/macros.md * mkdocs: document JSON_DisableEnumSerialization CMake option * mkdocs: encode required C++ standard in example files * docset: detect gsed/sed * docset: update index * docset: fix CSS patching * docset: add list_missing_pages make target * docset: add list_removed_paths make target * docset: replace page titles with name from index * docset: add install target for Zeal docset browser * Use GCC_TOOL in ci_test_documentation target
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2.2 KiB
JSON_DIAGNOSTICS
#define JSON_DIAGNOSTICS /* value */
This macro enables extended diagnostics for exception messages.
Possible values are 1 to enable or 0 to disable (default).
When enabled, exception messages contain a JSON Pointer to the JSON value that triggered the exception. Note that enabling this macro increases the size of every JSON value by one pointer and adds some runtime overhead.
Default definition
The default value is 0 (extended diagnostics are switched off).
#define JSON_DIAGNOSTICS 0
When the macro is not defined, the library will define it to its default value.
Notes
!!! note "ABI compatibility"
As of version 3.11.0, this macro is no longer required to be defined consistently throughout a codebase to avoid
One Definition Rule (ODR) violations, as the value of this macro is encoded in the namespace, resulting in distinct
symbol names.
This allows different parts of a codebase to use different versions or configurations of this library without
causing improper behavior.
Where possible, it is still recommended that all code define this the same way for maximum interoperability.
!!! hint "CMake option"
Diagnostic messages can also be controlled with the CMake option
[`JSON_Diagnostics`](../../integration/cmake.md#json_diagnostics) (`OFF` by default)
which defines `JSON_DIAGNOSTICS` accordingly.
Examples
??? example "Example 1: default behavior"
```cpp
--8<-- "examples/diagnostics_standard.cpp"
```
Output:
```
--8<-- "examples/diagnostics_standard.output"
```
This exception can be hard to debug if storing the value `#!c "12"` and accessing it is further apart.
??? example "Example 2: extended diagnostic messages"
```cpp
--8<-- "examples/diagnostics_extended.cpp"
```
Output:
```
--8<-- "examples/diagnostics_extended.output"
```
Now the exception message contains a JSON Pointer `/address/housenumber` that indicates which value has the wrong type.
Version history
- Added in version 3.10.0.
- As of version 3.11.0 the definition is allowed to vary between translation units.