xref: /freebsd/contrib/llvm-project/libcxx/include/__concepts/boolean_testable.h (revision 5f757f3ff9144b609b3c433dfd370cc6bdc191ad)
1349cc55cSDimitry Andric //===----------------------------------------------------------------------===//
2349cc55cSDimitry Andric //
3349cc55cSDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4349cc55cSDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
5349cc55cSDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6349cc55cSDimitry Andric //
7349cc55cSDimitry Andric //===----------------------------------------------------------------------===//
8349cc55cSDimitry Andric 
9349cc55cSDimitry Andric #ifndef _LIBCPP___CONCEPTS_BOOLEAN_TESTABLE_H
10349cc55cSDimitry Andric #define _LIBCPP___CONCEPTS_BOOLEAN_TESTABLE_H
11349cc55cSDimitry Andric 
12349cc55cSDimitry Andric #include <__concepts/convertible_to.h>
13349cc55cSDimitry Andric #include <__config>
14349cc55cSDimitry Andric #include <__utility/forward.h>
15349cc55cSDimitry Andric 
16349cc55cSDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17349cc55cSDimitry Andric #  pragma GCC system_header
18349cc55cSDimitry Andric #endif
19349cc55cSDimitry Andric 
20349cc55cSDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD
21349cc55cSDimitry Andric 
2206c3fb27SDimitry Andric #if _LIBCPP_STD_VER >= 20
23349cc55cSDimitry Andric 
24349cc55cSDimitry Andric // [concepts.booleantestable]
25349cc55cSDimitry Andric 
26349cc55cSDimitry Andric template <class _Tp>
27349cc55cSDimitry Andric concept __boolean_testable_impl = convertible_to<_Tp, bool>;
28349cc55cSDimitry Andric 
29349cc55cSDimitry Andric template <class _Tp>
30349cc55cSDimitry Andric concept __boolean_testable = __boolean_testable_impl<_Tp> && requires(_Tp&& __t) {
31*5f757f3fSDimitry Andric   { !std::forward<_Tp>(__t) } -> __boolean_testable_impl;
32349cc55cSDimitry Andric };
33349cc55cSDimitry Andric 
3406c3fb27SDimitry Andric #endif // _LIBCPP_STD_VER >= 20
35349cc55cSDimitry Andric 
36349cc55cSDimitry Andric _LIBCPP_END_NAMESPACE_STD
37349cc55cSDimitry Andric 
38349cc55cSDimitry Andric #endif // _LIBCPP___CONCEPTS_BOOLEAN_TESTABLE_H
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