xref: /llvm-project/libcxx/include/__cxx03/__concepts/boolean_testable.h (revision ce7771902dc50d900de639d499a60486b83f70e0)
1e78f53d1SNikolas Klauser //===----------------------------------------------------------------------===//
2e78f53d1SNikolas Klauser //
3e78f53d1SNikolas Klauser // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4e78f53d1SNikolas Klauser // See https://llvm.org/LICENSE.txt for license information.
5e78f53d1SNikolas Klauser // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6e78f53d1SNikolas Klauser //
7e78f53d1SNikolas Klauser //===----------------------------------------------------------------------===//
8e78f53d1SNikolas Klauser 
9*ce777190SNikolas Klauser #ifndef _LIBCPP___CXX03___CONCEPTS_BOOLEAN_TESTABLE_H
10*ce777190SNikolas Klauser #define _LIBCPP___CXX03___CONCEPTS_BOOLEAN_TESTABLE_H
11e78f53d1SNikolas Klauser 
1273fbae83SNikolas Klauser #include <__cxx03/__concepts/convertible_to.h>
1373fbae83SNikolas Klauser #include <__cxx03/__config>
1473fbae83SNikolas Klauser #include <__cxx03/__utility/forward.h>
15e78f53d1SNikolas Klauser 
16e78f53d1SNikolas Klauser #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17e78f53d1SNikolas Klauser #  pragma GCC system_header
18e78f53d1SNikolas Klauser #endif
19e78f53d1SNikolas Klauser 
20e78f53d1SNikolas Klauser _LIBCPP_BEGIN_NAMESPACE_STD
21e78f53d1SNikolas Klauser 
22e78f53d1SNikolas Klauser #if _LIBCPP_STD_VER >= 20
23e78f53d1SNikolas Klauser 
24e78f53d1SNikolas Klauser // [concepts.booleantestable]
25e78f53d1SNikolas Klauser 
26e78f53d1SNikolas Klauser template <class _Tp>
27e78f53d1SNikolas Klauser concept __boolean_testable_impl = convertible_to<_Tp, bool>;
28e78f53d1SNikolas Klauser 
29e78f53d1SNikolas Klauser template <class _Tp>
30e78f53d1SNikolas Klauser concept __boolean_testable = __boolean_testable_impl<_Tp> && requires(_Tp&& __t) {
31e78f53d1SNikolas Klauser   { !std::forward<_Tp>(__t) } -> __boolean_testable_impl;
32e78f53d1SNikolas Klauser };
33e78f53d1SNikolas Klauser 
34e78f53d1SNikolas Klauser #endif // _LIBCPP_STD_VER >= 20
35e78f53d1SNikolas Klauser 
36e78f53d1SNikolas Klauser _LIBCPP_END_NAMESPACE_STD
37e78f53d1SNikolas Klauser 
38*ce777190SNikolas Klauser #endif // _LIBCPP___CXX03___CONCEPTS_BOOLEAN_TESTABLE_H
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