libcxx/include/__tuple/pair_like.h

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef _LIBCPP___TUPLE_PAIR_LIKE_H
  10 #define _LIBCPP___TUPLE_PAIR_LIKE_H
  11
  12 #include <__config>
  13 #include <__tuple/tuple_like.h>
  14 #include <__tuple/tuple_size.h>
  15 #include <__type_traits/remove_cvref.h>
  16
  17 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  18 #  pragma GCC system_header
  19 #endif
  20
  21 _LIBCPP_BEGIN_NAMESPACE_STD
  22
  23 #if _LIBCPP_STD_VER >= 20
  24
  25 template <class _Tp>
  26 concept __pair_like = __tuple_like<_Tp> && tuple_size<remove_cvref_t<_Tp>>::value == 2;
  27
  28 #endif // _LIBCPP_STD_VER >= 20
  29
  30 _LIBCPP_END_NAMESPACE_STD
  31
  32 #endif // _LIBCPP___TUPLE_PAIR_LIKE_H