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nlohmann
41 lines
1.5 KiB
Markdown
41 lines
1.5 KiB
Markdown
# JSON_HAS_CPP_11, JSON_HAS_CPP_14, JSON_HAS_CPP_17, JSON_HAS_CPP_20, JSON_HAS_CPP_23, JSON_HAS_CPP_26
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```
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#define JSON_HAS_CPP_11
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#define JSON_HAS_CPP_14
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#define JSON_HAS_CPP_17
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#define JSON_HAS_CPP_20
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#define JSON_HAS_CPP_23
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#define JSON_HAS_CPP_26
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```
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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.
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## Default definition
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The default value is detected based on preprocessor macros such as `__cplusplus`, `_HAS_CXX17`, or `_MSVC_LANG`.
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## Notes
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- When the C++ standard is detected automatically, `JSON_HAS_CPP_11` is 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 `JSON_HAS_CPP_11`) yourself.
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- All macros are undefined outside the library.
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## Examples
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Example
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The code below forces the library to use the C++14 standard:
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```
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#define JSON_HAS_CPP_14 1
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#include <nlohmann/json.hpp>
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...
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```
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## Version history
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- Added in version 3.10.5.
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- Added `JSON_HAS_CPP_23` in version 3.12.0.
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- Added `JSON_HAS_CPP_26` in version 3.13.0.
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