26a3f288f1
The coroutine_handle<void>::from_address(void*) version is already noexcept, and they do the same thing. Make them consistent. libstdc++-v3/ChangeLog: PR libstdc++/99021 * include/std/coroutine (coroutine_handle<P>::from_address): Add noexcept.
343 lines
8.9 KiB
C++
343 lines
8.9 KiB
C++
// <coroutine> -*- C++ -*-
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// Copyright (C) 2019-2021 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/** @file include/coroutine
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* This is a Standard C++ Library header.
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*/
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#ifndef _GLIBCXX_COROUTINE
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#define _GLIBCXX_COROUTINE 1
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#pragma GCC system_header
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// It is very likely that earlier versions would work, but they are untested.
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#if __cplusplus >= 201402L
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#include <bits/c++config.h>
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/**
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* @defgroup coroutines Coroutines
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*
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* Components for supporting coroutine implementations.
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*/
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#if __cplusplus > 201703L && __cpp_impl_three_way_comparison >= 201907L
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# include <compare>
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# define _COROUTINES_USE_SPACESHIP 1
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#else
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# include <bits/stl_function.h> // for std::less
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# define _COROUTINES_USE_SPACESHIP 0
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#endif
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namespace std _GLIBCXX_VISIBILITY (default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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#if __cpp_impl_coroutine
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#define __cpp_lib_coroutine 201902L
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inline namespace __n4861 {
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// 17.12.2 coroutine traits
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/// [coroutine.traits]
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/// [coroutine.traits.primary]
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/// If _Result::promise_type is valid and denotes a type then the traits
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/// have a single publicly accessible member, otherwise they are empty.
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template <typename _Result, typename = void>
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struct __coroutine_traits_impl {};
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template <typename _Result>
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struct __coroutine_traits_impl<_Result,
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__void_t<typename _Result::promise_type>>
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{
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using promise_type = typename _Result::promise_type;
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};
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template <typename _Result, typename...>
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struct coroutine_traits : __coroutine_traits_impl<_Result> {};
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// 17.12.3 Class template coroutine_handle
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/// [coroutine.handle]
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template <typename _Promise = void>
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struct coroutine_handle;
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template <> struct
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coroutine_handle<void>
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{
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public:
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// [coroutine.handle.con], construct/reset
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constexpr coroutine_handle() noexcept : _M_fr_ptr(0) {}
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constexpr coroutine_handle(std::nullptr_t __h) noexcept
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: _M_fr_ptr(__h)
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{}
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coroutine_handle& operator=(std::nullptr_t) noexcept
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{
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_M_fr_ptr = nullptr;
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return *this;
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}
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public:
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// [coroutine.handle.export.import], export/import
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constexpr void* address() const noexcept { return _M_fr_ptr; }
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constexpr static coroutine_handle from_address(void* __a) noexcept
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{
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coroutine_handle __self;
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__self._M_fr_ptr = __a;
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return __self;
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}
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public:
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// [coroutine.handle.observers], observers
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constexpr explicit operator bool() const noexcept
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{
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return bool(_M_fr_ptr);
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}
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bool done() const noexcept { return __builtin_coro_done(_M_fr_ptr); }
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// [coroutine.handle.resumption], resumption
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void operator()() const { resume(); }
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void resume() const { __builtin_coro_resume(_M_fr_ptr); }
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void destroy() const { __builtin_coro_destroy(_M_fr_ptr); }
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protected:
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void* _M_fr_ptr;
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};
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// [coroutine.handle.compare], comparison operators
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constexpr bool
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operator==(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
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{
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return __a.address() == __b.address();
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}
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#if _COROUTINES_USE_SPACESHIP
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constexpr strong_ordering
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operator<=>(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
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{
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return std::compare_three_way()(__a.address(), __b.address());
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}
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#else
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// These are to enable operation with std=c++14,17.
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constexpr bool
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operator!=(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
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{
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return !(__a == __b);
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}
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constexpr bool
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operator<(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
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{
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return less<void*>()(__a.address(), __b.address());
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}
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constexpr bool
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operator>(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
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{
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return __b < __a;
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}
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constexpr bool
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operator<=(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
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{
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return !(__a > __b);
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}
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constexpr bool
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operator>=(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
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{
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return !(__a < __b);
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}
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#endif
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template <typename _Promise>
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struct coroutine_handle
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{
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// [coroutine.handle.con], construct/reset
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constexpr coroutine_handle() noexcept { }
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constexpr coroutine_handle(nullptr_t) noexcept { }
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static coroutine_handle
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from_promise(_Promise& __p)
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{
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coroutine_handle __self;
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__self._M_fr_ptr
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= __builtin_coro_promise((char*) &__p, __alignof(_Promise), true);
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return __self;
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}
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coroutine_handle& operator=(nullptr_t) noexcept
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{
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_M_fr_ptr = nullptr;
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return *this;
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}
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// [coroutine.handle.export.import], export/import
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constexpr void* address() const noexcept { return _M_fr_ptr; }
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constexpr static coroutine_handle from_address(void* __a) noexcept
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{
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coroutine_handle __self;
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__self._M_fr_ptr = __a;
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return __self;
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}
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// [coroutine.handle.conv], conversion
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constexpr operator coroutine_handle<>() const noexcept
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{ return coroutine_handle<>::from_address(address()); }
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// [coroutine.handle.observers], observers
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constexpr explicit operator bool() const noexcept
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{
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return bool(_M_fr_ptr);
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}
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bool done() const noexcept { return __builtin_coro_done(_M_fr_ptr); }
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// [coroutine.handle.resumption], resumption
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void operator()() const { resume(); }
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void resume() const { __builtin_coro_resume(_M_fr_ptr); }
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void destroy() const { __builtin_coro_destroy(_M_fr_ptr); }
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// [coroutine.handle.promise], promise access
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_Promise& promise() const
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{
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void* __t
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= __builtin_coro_promise (_M_fr_ptr, __alignof(_Promise), false);
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return *static_cast<_Promise*>(__t);
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}
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private:
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void* _M_fr_ptr = nullptr;
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};
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/// [coroutine.noop]
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struct noop_coroutine_promise
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{
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};
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// 17.12.4.1 Class noop_coroutine_promise
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/// [coroutine.promise.noop]
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template <>
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struct coroutine_handle<noop_coroutine_promise>
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{
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// _GLIBCXX_RESOLVE_LIB_DEFECTS
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// 3460. Unimplementable noop_coroutine_handle guarantees
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// [coroutine.handle.noop.conv], conversion
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constexpr operator coroutine_handle<>() const noexcept
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{ return coroutine_handle<>::from_address(address()); }
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// [coroutine.handle.noop.observers], observers
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constexpr explicit operator bool() const noexcept { return true; }
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constexpr bool done() const noexcept { return false; }
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// [coroutine.handle.noop.resumption], resumption
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void operator()() const noexcept {}
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void resume() const noexcept {}
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void destroy() const noexcept {}
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// [coroutine.handle.noop.promise], promise access
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noop_coroutine_promise& promise() const noexcept
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{ return _S_fr.__p; }
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// [coroutine.handle.noop.address], address
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constexpr void* address() const noexcept { return _M_fr_ptr; }
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private:
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friend coroutine_handle noop_coroutine() noexcept;
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struct __frame
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{
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static void __dummy_resume_destroy() { }
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void (*__r)() = __dummy_resume_destroy;
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void (*__d)() = __dummy_resume_destroy;
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struct noop_coroutine_promise __p;
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};
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static __frame _S_fr;
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explicit coroutine_handle() noexcept = default;
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void* _M_fr_ptr = &_S_fr;
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};
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using noop_coroutine_handle = coroutine_handle<noop_coroutine_promise>;
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inline noop_coroutine_handle::__frame
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noop_coroutine_handle::_S_fr{};
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inline noop_coroutine_handle noop_coroutine() noexcept
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{
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return noop_coroutine_handle();
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}
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// 17.12.5 Trivial awaitables
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/// [coroutine.trivial.awaitables]
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struct suspend_always
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{
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constexpr bool await_ready() const noexcept { return false; }
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constexpr void await_suspend(coroutine_handle<>) const noexcept {}
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constexpr void await_resume() const noexcept {}
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};
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struct suspend_never
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{
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constexpr bool await_ready() const noexcept { return true; }
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constexpr void await_suspend(coroutine_handle<>) const noexcept {}
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constexpr void await_resume() const noexcept {}
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};
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} // namespace __n4861
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#else
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#error "the coroutine header requires -fcoroutines"
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#endif
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_GLIBCXX_END_NAMESPACE_VERSION
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} // namespace std
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#endif // C++14 (we are allowing use from at least this)
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#endif // _GLIBCXX_COROUTINE
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