xref: /openbsd-src/gnu/llvm/libcxx/include/__concepts/boolean_testable.h (revision 4bdff4bed0e3d54e55670334c7d0077db4170f86)
1*4bdff4beSrobert //===----------------------------------------------------------------------===//
2*4bdff4beSrobert //
3*4bdff4beSrobert // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4*4bdff4beSrobert // See https://llvm.org/LICENSE.txt for license information.
5*4bdff4beSrobert // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6*4bdff4beSrobert //
7*4bdff4beSrobert //===----------------------------------------------------------------------===//
8*4bdff4beSrobert 
9*4bdff4beSrobert #ifndef _LIBCPP___CONCEPTS_BOOLEAN_TESTABLE_H
10*4bdff4beSrobert #define _LIBCPP___CONCEPTS_BOOLEAN_TESTABLE_H
11*4bdff4beSrobert 
12*4bdff4beSrobert #include <__concepts/convertible_to.h>
13*4bdff4beSrobert #include <__config>
14*4bdff4beSrobert #include <__utility/forward.h>
15*4bdff4beSrobert 
16*4bdff4beSrobert #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17*4bdff4beSrobert #  pragma GCC system_header
18*4bdff4beSrobert #endif
19*4bdff4beSrobert 
20*4bdff4beSrobert _LIBCPP_BEGIN_NAMESPACE_STD
21*4bdff4beSrobert 
22*4bdff4beSrobert #if _LIBCPP_STD_VER > 17
23*4bdff4beSrobert 
24*4bdff4beSrobert // [concepts.booleantestable]
25*4bdff4beSrobert 
26*4bdff4beSrobert template<class _Tp>
27*4bdff4beSrobert concept __boolean_testable_impl = convertible_to<_Tp, bool>;
28*4bdff4beSrobert 
29*4bdff4beSrobert template<class _Tp>
requires(_Tp && __t)30*4bdff4beSrobert concept __boolean_testable = __boolean_testable_impl<_Tp> && requires(_Tp&& __t) {
31*4bdff4beSrobert   { !_VSTD::forward<_Tp>(__t) } -> __boolean_testable_impl;
32*4bdff4beSrobert };
33*4bdff4beSrobert 
34*4bdff4beSrobert #endif // _LIBCPP_STD_VER > 17
35*4bdff4beSrobert 
36*4bdff4beSrobert _LIBCPP_END_NAMESPACE_STD
37*4bdff4beSrobert 
38*4bdff4beSrobert #endif // _LIBCPP___CONCEPTS_BOOLEAN_TESTABLE_H
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