xref: /freebsd/contrib/llvm-project/libcxx/include/__functional/mem_fn.h (revision 1db9f3b21e39176dd5b67cf8ac378633b172463e)
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 
10 #ifndef _LIBCPP___FUNCTIONAL_MEM_FN_H
11 #define _LIBCPP___FUNCTIONAL_MEM_FN_H
12 
13 #include <__config>
14 #include <__functional/binary_function.h>
15 #include <__functional/invoke.h>
16 #include <__functional/weak_result_type.h>
17 #include <__utility/forward.h>
18 
19 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
20 #  pragma GCC system_header
21 #endif
22 
23 _LIBCPP_BEGIN_NAMESPACE_STD
24 
25 template <class _Tp>
26 class __mem_fn : public __weak_result_type<_Tp> {
27 public:
28   // types
29   typedef _Tp type;
30 
31 private:
32   type __f_;
33 
34 public:
35   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __mem_fn(type __f) _NOEXCEPT : __f_(__f) {}
36 
37   // invoke
38   template <class... _ArgTypes>
39   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
40 
41       typename __invoke_return<type, _ArgTypes...>::type
42       operator()(_ArgTypes&&... __args) const {
43     return std::__invoke(__f_, std::forward<_ArgTypes>(__args)...);
44   }
45 };
46 
47 template <class _Rp, class _Tp>
48 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __mem_fn<_Rp _Tp::*> mem_fn(_Rp _Tp::*__pm) _NOEXCEPT {
49   return __mem_fn<_Rp _Tp::*>(__pm);
50 }
51 
52 _LIBCPP_END_NAMESPACE_STD
53 
54 #endif // _LIBCPP___FUNCTIONAL_MEM_FN_H
55