llvm-project/libcxx/include/__functional/bind_front.h

53 lines
1.8 KiB
C++

// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___FUNCTIONAL_BIND_FRONT_H
#define _LIBCPP___FUNCTIONAL_BIND_FRONT_H
#include <__config>
#include <__functional/perfect_forward.h>
#include <__functional/invoke.h>
#include <type_traits>
#include <utility>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER > 17
struct __bind_front_op
{
template<class... _Args>
constexpr static auto __call(_Args&&... __args)
noexcept(noexcept(_VSTD::invoke(_VSTD::forward<_Args>(__args)...)))
-> decltype( _VSTD::invoke(_VSTD::forward<_Args>(__args)...))
{ return _VSTD::invoke(_VSTD::forward<_Args>(__args)...); }
};
template<class _Fn, class... _Args,
class = _EnableIf<conjunction<is_constructible<decay_t<_Fn>, _Fn>,
is_move_constructible<decay_t<_Fn>>,
is_constructible<decay_t<_Args>, _Args>...,
is_move_constructible<decay_t<_Args>>...
>::value>>
constexpr auto bind_front(_Fn&& __f, _Args&&... __args)
{
return __perfect_forward<__bind_front_op, _Fn, _Args...>(_VSTD::forward<_Fn>(__f),
_VSTD::forward<_Args>(__args)...);
}
#endif // _LIBCPP_STD_VER > 17
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___FUNCTIONAL_BIND_FRONT_H