fast_float/include/fast_float/constexpr_feature_detect.h
Aras Pranckevičius 21fefa5b44
Fix warnings with -Wundef
- FASTFLOAT_ALLOWS_LEADING_PLUS and FASTFLOAT_SKIP_WHITE_SPACE are not defined by default, and compiling with -Wundef is emitting warnigns like "FASTFLOAT_ALLOWS_LEADING_PLUS is not defined, evaluates to 0".
- Likewise for FASTFLOAT_VISUAL_STUDIO, change checks to use #ifdef for that like in other places.
- __cpp_lib_bit_cast and __cpp_lib_is_constant_evaluated are not defined pre-C++20, and are emitting a warning too.
2023-04-04 21:18:57 +03:00

41 lines
1.1 KiB
C++

#ifndef FASTFLOAT_CONSTEXPR_FEATURE_DETECT_H
#define FASTFLOAT_CONSTEXPR_FEATURE_DETECT_H
#ifdef __has_include
#if __has_include(<version>)
#include <version>
#endif
#endif
// Testing for https://wg21.link/N3652, adopted in C++14
#if __cpp_constexpr >= 201304
#define FASTFLOAT_CONSTEXPR14 constexpr
#else
#define FASTFLOAT_CONSTEXPR14
#endif
#if defined(__cpp_lib_bit_cast) && __cpp_lib_bit_cast >= 201806L
#define FASTFLOAT_HAS_BIT_CAST 1
#else
#define FASTFLOAT_HAS_BIT_CAST 0
#endif
#if defined(__cpp_lib_is_constant_evaluated) && __cpp_lib_is_constant_evaluated >= 201811L
#define FASTFLOAT_HAS_IS_CONSTANT_EVALUATED 1
#else
#define FASTFLOAT_HAS_IS_CONSTANT_EVALUATED 0
#endif
// Testing for relevant C++20 constexpr library features
#if FASTFLOAT_HAS_IS_CONSTANT_EVALUATED \
&& FASTFLOAT_HAS_BIT_CAST \
&& __cpp_lib_constexpr_algorithms >= 201806L /*For std::copy and std::fill*/
#define FASTFLOAT_CONSTEXPR20 constexpr
#define FASTFLOAT_IS_CONSTEXPR 1
#else
#define FASTFLOAT_CONSTEXPR20
#define FASTFLOAT_IS_CONSTEXPR 0
#endif
#endif // FASTFLOAT_CONSTEXPR_FEATURE_DETECT_H