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nlohmann
42 lines
1.0 KiB
Markdown
42 lines
1.0 KiB
Markdown
# JSON_HAS_STD_FORMAT
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```cpp
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#define JSON_HAS_STD_FORMAT /* value */
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```
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This macro indicates whether the standard library has support for `std::format`/`std::formatter` (that
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is, the `<format>` header). Possible values are `1` when supported or `0` when unsupported.
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## Default definition
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The default value is detected based on the preprocessor macros `#!cpp JSON_HAS_CPP_20` and
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`#!cpp __cpp_lib_format`.
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When the macro is not defined, the library will define it to its default value.
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## Notes
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!!! info "Enabled functionality"
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When this macro evaluates to `1`, the library provides a
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[`std::formatter<basic_json>`](../basic_json/std_formatter.md) specialization so JSON values can be
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used directly with `std::format`.
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## Examples
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??? example
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The code below forces the library to disable support for `std::format`, even if the standard library
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would otherwise support it:
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```cpp
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#define JSON_HAS_STD_FORMAT 0
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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 3.13.0.
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