xref: /openbsd-src/gnu/llvm/libcxx/include/__functional/bind_front.h (revision 4bdff4bed0e3d54e55670334c7d0077db4170f86)
176d0caaeSpatrick // -*- C++ -*-
276d0caaeSpatrick //===----------------------------------------------------------------------===//
376d0caaeSpatrick //
476d0caaeSpatrick // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
576d0caaeSpatrick // See https://llvm.org/LICENSE.txt for license information.
676d0caaeSpatrick // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
776d0caaeSpatrick //
876d0caaeSpatrick //===----------------------------------------------------------------------===//
976d0caaeSpatrick 
1076d0caaeSpatrick #ifndef _LIBCPP___FUNCTIONAL_BIND_FRONT_H
1176d0caaeSpatrick #define _LIBCPP___FUNCTIONAL_BIND_FRONT_H
1276d0caaeSpatrick 
1376d0caaeSpatrick #include <__config>
1476d0caaeSpatrick #include <__functional/invoke.h>
15*4bdff4beSrobert #include <__functional/perfect_forward.h>
16*4bdff4beSrobert #include <__utility/forward.h>
1776d0caaeSpatrick #include <type_traits>
1876d0caaeSpatrick 
1976d0caaeSpatrick #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
2076d0caaeSpatrick #  pragma GCC system_header
2176d0caaeSpatrick #endif
2276d0caaeSpatrick 
2376d0caaeSpatrick _LIBCPP_BEGIN_NAMESPACE_STD
2476d0caaeSpatrick 
2576d0caaeSpatrick #if _LIBCPP_STD_VER > 17
2676d0caaeSpatrick 
27*4bdff4beSrobert struct __bind_front_op {
2876d0caaeSpatrick     template <class ..._Args>
29*4bdff4beSrobert     _LIBCPP_HIDE_FROM_ABI
30*4bdff4beSrobert     constexpr auto operator()(_Args&& ...__args) const
3176d0caaeSpatrick         noexcept(noexcept(_VSTD::invoke(_VSTD::forward<_Args>(__args)...)))
3276d0caaeSpatrick         -> decltype(      _VSTD::invoke(_VSTD::forward<_Args>(__args)...))
3376d0caaeSpatrick         { return          _VSTD::invoke(_VSTD::forward<_Args>(__args)...); }
3476d0caaeSpatrick };
3576d0caaeSpatrick 
36*4bdff4beSrobert template <class _Fn, class ..._BoundArgs>
37*4bdff4beSrobert struct __bind_front_t : __perfect_forward<__bind_front_op, _Fn, _BoundArgs...> {
38*4bdff4beSrobert     using __perfect_forward<__bind_front_op, _Fn, _BoundArgs...>::__perfect_forward;
39*4bdff4beSrobert };
40*4bdff4beSrobert 
41*4bdff4beSrobert template <class _Fn, class... _Args, class = enable_if_t<
42*4bdff4beSrobert     _And<
43*4bdff4beSrobert         is_constructible<decay_t<_Fn>, _Fn>,
4476d0caaeSpatrick         is_move_constructible<decay_t<_Fn>>,
4576d0caaeSpatrick         is_constructible<decay_t<_Args>, _Args>...,
4676d0caaeSpatrick         is_move_constructible<decay_t<_Args>>...
47*4bdff4beSrobert     >::value
48*4bdff4beSrobert >>
49*4bdff4beSrobert _LIBCPP_HIDE_FROM_ABI
bind_front(_Fn && __f,_Args &&...__args)50*4bdff4beSrobert constexpr auto bind_front(_Fn&& __f, _Args&&... __args) {
51*4bdff4beSrobert     return __bind_front_t<decay_t<_Fn>, decay_t<_Args>...>(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)...);
5276d0caaeSpatrick }
5376d0caaeSpatrick 
5476d0caaeSpatrick #endif // _LIBCPP_STD_VER > 17
5576d0caaeSpatrick 
5676d0caaeSpatrick _LIBCPP_END_NAMESPACE_STD
5776d0caaeSpatrick 
5876d0caaeSpatrick #endif // _LIBCPP___FUNCTIONAL_BIND_FRONT_H
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