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521a084827
* 📝 Fix documentation gaps for 3.13.0 release (todos 138-142) - Todo 138: Add "Known issues" section to modules.md with compiler-specific troubleshooting (GCC redefinition, MSVC symbol export). Add pointer note to quality_assurance.md. - Todo 139: Document CBOR/MessagePack half-precision float encoding for NaN/Infinity (0xF9/0xCA with exact byte sequences). Explain pre-3.13.0 double-precision bug mechanism without issue citations. - Todo 140: Document CBOR negative-integer-overflow rejection (parse_error.112) for magnitudes exceeding int64_t range (already implemented in rev 1). - Todo 141: Update version history in value.md and operator[].md with behavior-change details, removing issue citations per citation policy (prose is self-contained). - Todo 142: Global sed replace of 3.12.x → 3.13.0 placeholder across all 20 documentation files. Revision 2 incorporates feedback to reduce changelog-like issue citations. Only citations that add unique troubleshooting value are retained (#5103 for GCC workaround, #3970 for MSVC symbol export). "Known issues" section follows PR #5252's visual pattern (info admonition with bold-bullet format). Signed-off-by: Niels Lohmann <mail@nlohmann.me> * 📝 Document integer type selection, type_name() invalid value, and std::optional get() fix - number_handling.md: clarify that positive/negative integers select unsigned/signed storage based on the leading minus sign (todo 143). - type_name.md: document the new "invalid" return value for corrupted JSON values (todo 145). - get.md: note that get<std::optional<T>>() was unreachable in every configuration prior to 3.13.0 due to an internal macro-guard bug, unrelated to JSON_USE_IMPLICIT_CONVERSIONS's actual effect (todo 144). Signed-off-by: Niels Lohmann <mail@nlohmann.me> --------- Signed-off-by: Niels Lohmann <mail@nlohmann.me>
1.5 KiB
1.5 KiB
JSON_HAS_CPP_11, JSON_HAS_CPP_14, JSON_HAS_CPP_17, JSON_HAS_CPP_20, JSON_HAS_CPP_23, JSON_HAS_CPP_26
#define JSON_HAS_CPP_11
#define JSON_HAS_CPP_14
#define JSON_HAS_CPP_17
#define JSON_HAS_CPP_20
#define JSON_HAS_CPP_23
#define JSON_HAS_CPP_26
The library targets C++11, but also supports some features introduced in later C++ versions (e.g., std::string_view
support for C++17). For these new features, the library implements some preprocessor checks to determine the C++
standard. By defining any of these symbols, the internal check is overridden and the provided C++ version is
unconditionally assumed. This can be helpful for compilers that only implement parts of the standard and would be
detected incorrectly.
Default definition
The default value is detected based on preprocessor macros such as #!cpp __cplusplus, #!cpp _HAS_CXX17, or
#!cpp _MSVC_LANG.
Notes
- When the C++ standard is detected automatically,
#!cpp JSON_HAS_CPP_11is always defined. When you override the detection by defining one of these macros manually, the automatic detection is skipped entirely, so you should define all applicable macros (including#!cpp JSON_HAS_CPP_11) yourself. - All macros are undefined outside the library.
Examples
??? example
The code below forces the library to use the C++14 standard:
```cpp
#define JSON_HAS_CPP_14 1
#include <nlohmann/json.hpp>
...
```
Version history
- Added in version 3.10.5.
- Added
JSON_HAS_CPP_23in version 3.12.0. - Added
JSON_HAS_CPP_26in version 3.13.0.