From cppreference.com
This header is part of the
library, providing
fixed width floating-point types
.
Notes
The fixed width floating-point types must be aliases to extended floating-point types (not float / double / longdouble), therefore not drop-in replacements for standard floating-point types.
Synopsis
namespacestd{#if defined(__STDCPP_FLOAT16_T__)usingfloat16_t=/* implementation-defined */;#endif#if defined(__STDCPP_FLOAT32_T__)usingfloat32_t=/* implementation-defined */;#endif#if defined(__STDCPP_FLOAT64_T__)usingfloat64_t=/* implementation-defined */;#endif#if defined(__STDCPP_FLOAT128_T__)usingfloat128_t=/* implementation-defined */;#endif#if defined(__STDCPP_BFLOAT16_T__)usingbfloat16_t=/* implementation-defined */;#endif}References
C++23 standard (ISO/IEC 14882:2024):
17.5 Header <stdfloat> synopsis [stdfloat.syn]