to_underlying.h 1.1 KB

12345678910111213141516171819202122232425262728293031323334353637383940
  1. // -*- C++ -*-
  2. //===----------------------------------------------------------------------===//
  3. //
  4. // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  5. // See https://llvm.org/LICENSE.txt for license information.
  6. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  7. //
  8. //===----------------------------------------------------------------------===//
  9. #ifndef _LIBCPP___UTILITY_TO_UNDERLYING_H
  10. #define _LIBCPP___UTILITY_TO_UNDERLYING_H
  11. #include <__config>
  12. #include <type_traits>
  13. #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  14. # pragma GCC system_header
  15. #endif
  16. _LIBCPP_BEGIN_NAMESPACE_STD
  17. #ifndef _LIBCPP_CXX03_LANG
  18. template <class _Tp>
  19. _LIBCPP_INLINE_VISIBILITY constexpr typename underlying_type<_Tp>::type
  20. __to_underlying(_Tp __val) noexcept {
  21. return static_cast<typename underlying_type<_Tp>::type>(__val);
  22. }
  23. #endif // !_LIBCPP_CXX03_LANG
  24. #if _LIBCPP_STD_VER > 20
  25. template <class _Tp>
  26. _LIBCPP_NODISCARD_EXT _LIBCPP_INLINE_VISIBILITY constexpr underlying_type_t<_Tp>
  27. to_underlying(_Tp __val) noexcept {
  28. return _VSTD::__to_underlying(__val);
  29. }
  30. #endif
  31. _LIBCPP_END_NAMESPACE_STD
  32. #endif // _LIBCPP___UTILITY_TO_UNDERLYING_H