Bug Summary

File:build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/llvm/lib/ExecutionEngine/Orc/ExecutorProcessControl.cpp
Warning:line 199, column 11
Potential leak of memory pointed to by field '_M_head_impl'

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name ExecutorProcessControl.cpp -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/build-llvm/tools/clang/stage2-bins -resource-dir /usr/lib/llvm-16/lib/clang/16.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I lib/ExecutionEngine/Orc -I /build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/llvm/lib/ExecutionEngine/Orc -I include -I /build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/llvm/include -D _FORTIFY_SOURCE=2 -D NDEBUG -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-16/lib/clang/16.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fmacro-prefix-map=/build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/build-llvm/tools/clang/stage2-bins=build-llvm/tools/clang/stage2-bins -fmacro-prefix-map=/build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/= -fcoverage-prefix-map=/build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/build-llvm/tools/clang/stage2-bins=build-llvm/tools/clang/stage2-bins -fcoverage-prefix-map=/build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/= -O2 -Wno-unused-command-line-argument -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -Wno-misleading-indentation -std=c++17 -fdeprecated-macro -fdebug-compilation-dir=/build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/build-llvm/tools/clang/stage2-bins -fdebug-prefix-map=/build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/build-llvm/tools/clang/stage2-bins=build-llvm/tools/clang/stage2-bins -fdebug-prefix-map=/build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/= -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -fcolor-diagnostics -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2022-09-04-125545-48738-1 -x c++ /build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/llvm/lib/ExecutionEngine/Orc/ExecutorProcessControl.cpp

/build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/llvm/lib/ExecutionEngine/Orc/ExecutorProcessControl.cpp

1//===---- ExecutorProcessControl.cpp -- Executor process control APIs -----===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "llvm/ExecutionEngine/Orc/ExecutorProcessControl.h"
10
11#include "llvm/ExecutionEngine/Orc/Core.h"
12#include "llvm/ExecutionEngine/Orc/TargetProcess/TargetExecutionUtils.h"
13#include "llvm/Support/FormatVariadic.h"
14#include "llvm/Support/Host.h"
15#include "llvm/Support/Process.h"
16
17#define DEBUG_TYPE"orc" "orc"
18
19namespace llvm {
20namespace orc {
21
22ExecutorProcessControl::MemoryAccess::~MemoryAccess() = default;
23
24ExecutorProcessControl::~ExecutorProcessControl() = default;
25
26SelfExecutorProcessControl::SelfExecutorProcessControl(
27 std::shared_ptr<SymbolStringPool> SSP, std::unique_ptr<TaskDispatcher> D,
28 Triple TargetTriple, unsigned PageSize,
29 std::unique_ptr<jitlink::JITLinkMemoryManager> MemMgr)
30 : ExecutorProcessControl(std::move(SSP), std::move(D)) {
31
32 OwnedMemMgr = std::move(MemMgr);
33 if (!OwnedMemMgr)
34 OwnedMemMgr = std::make_unique<jitlink::InProcessMemoryManager>(
35 sys::Process::getPageSizeEstimate());
36
37 this->TargetTriple = std::move(TargetTriple);
38 this->PageSize = PageSize;
39 this->MemMgr = OwnedMemMgr.get();
40 this->MemAccess = this;
41 this->JDI = {ExecutorAddr::fromPtr(jitDispatchViaWrapperFunctionManager),
42 ExecutorAddr::fromPtr(this)};
43 if (this->TargetTriple.isOSBinFormatMachO())
44 GlobalManglingPrefix = '_';
45}
46
47Expected<std::unique_ptr<SelfExecutorProcessControl>>
48SelfExecutorProcessControl::Create(
49 std::shared_ptr<SymbolStringPool> SSP,
50 std::unique_ptr<TaskDispatcher> D,
51 std::unique_ptr<jitlink::JITLinkMemoryManager> MemMgr) {
52
53 if (!SSP)
54 SSP = std::make_shared<SymbolStringPool>();
55
56 if (!D) {
57#if LLVM_ENABLE_THREADS1
58 D = std::make_unique<DynamicThreadPoolTaskDispatcher>();
59#else
60 D = std::make_unique<InPlaceTaskDispatcher>();
61#endif
62 }
63
64 auto PageSize = sys::Process::getPageSize();
65 if (!PageSize)
66 return PageSize.takeError();
67
68 Triple TT(sys::getProcessTriple());
69
70 return std::make_unique<SelfExecutorProcessControl>(
71 std::move(SSP), std::move(D), std::move(TT), *PageSize,
72 std::move(MemMgr));
73}
74
75Expected<tpctypes::DylibHandle>
76SelfExecutorProcessControl::loadDylib(const char *DylibPath) {
77 std::string ErrMsg;
78 auto Dylib = std::make_unique<sys::DynamicLibrary>(
79 sys::DynamicLibrary::getPermanentLibrary(DylibPath, &ErrMsg));
80 if (!Dylib->isValid())
81 return make_error<StringError>(std::move(ErrMsg), inconvertibleErrorCode());
82 DynamicLibraries.push_back(std::move(Dylib));
83 return pointerToJITTargetAddress(DynamicLibraries.back().get());
84}
85
86Expected<std::vector<tpctypes::LookupResult>>
87SelfExecutorProcessControl::lookupSymbols(ArrayRef<LookupRequest> Request) {
88 std::vector<tpctypes::LookupResult> R;
89
90 for (auto &Elem : Request) {
91 auto *Dylib = jitTargetAddressToPointer<sys::DynamicLibrary *>(Elem.Handle);
92 assert(llvm::any_of(DynamicLibraries,(static_cast <bool> (llvm::any_of(DynamicLibraries, [=]
(const std::unique_ptr<sys::DynamicLibrary> &DL) { return
DL.get() == Dylib; }) && "Invalid handle") ? void (0
) : __assert_fail ("llvm::any_of(DynamicLibraries, [=](const std::unique_ptr<sys::DynamicLibrary> &DL) { return DL.get() == Dylib; }) && \"Invalid handle\""
, "llvm/lib/ExecutionEngine/Orc/ExecutorProcessControl.cpp", 96
, __extension__ __PRETTY_FUNCTION__))
93 [=](const std::unique_ptr<sys::DynamicLibrary> &DL) {(static_cast <bool> (llvm::any_of(DynamicLibraries, [=]
(const std::unique_ptr<sys::DynamicLibrary> &DL) { return
DL.get() == Dylib; }) && "Invalid handle") ? void (0
) : __assert_fail ("llvm::any_of(DynamicLibraries, [=](const std::unique_ptr<sys::DynamicLibrary> &DL) { return DL.get() == Dylib; }) && \"Invalid handle\""
, "llvm/lib/ExecutionEngine/Orc/ExecutorProcessControl.cpp", 96
, __extension__ __PRETTY_FUNCTION__))
94 return DL.get() == Dylib;(static_cast <bool> (llvm::any_of(DynamicLibraries, [=]
(const std::unique_ptr<sys::DynamicLibrary> &DL) { return
DL.get() == Dylib; }) && "Invalid handle") ? void (0
) : __assert_fail ("llvm::any_of(DynamicLibraries, [=](const std::unique_ptr<sys::DynamicLibrary> &DL) { return DL.get() == Dylib; }) && \"Invalid handle\""
, "llvm/lib/ExecutionEngine/Orc/ExecutorProcessControl.cpp", 96
, __extension__ __PRETTY_FUNCTION__))
95 }) &&(static_cast <bool> (llvm::any_of(DynamicLibraries, [=]
(const std::unique_ptr<sys::DynamicLibrary> &DL) { return
DL.get() == Dylib; }) && "Invalid handle") ? void (0
) : __assert_fail ("llvm::any_of(DynamicLibraries, [=](const std::unique_ptr<sys::DynamicLibrary> &DL) { return DL.get() == Dylib; }) && \"Invalid handle\""
, "llvm/lib/ExecutionEngine/Orc/ExecutorProcessControl.cpp", 96
, __extension__ __PRETTY_FUNCTION__))
96 "Invalid handle")(static_cast <bool> (llvm::any_of(DynamicLibraries, [=]
(const std::unique_ptr<sys::DynamicLibrary> &DL) { return
DL.get() == Dylib; }) && "Invalid handle") ? void (0
) : __assert_fail ("llvm::any_of(DynamicLibraries, [=](const std::unique_ptr<sys::DynamicLibrary> &DL) { return DL.get() == Dylib; }) && \"Invalid handle\""
, "llvm/lib/ExecutionEngine/Orc/ExecutorProcessControl.cpp", 96
, __extension__ __PRETTY_FUNCTION__))
;
97
98 R.push_back(std::vector<JITTargetAddress>());
99 for (auto &KV : Elem.Symbols) {
100 auto &Sym = KV.first;
101 std::string Tmp((*Sym).data() + !!GlobalManglingPrefix,
102 (*Sym).size() - !!GlobalManglingPrefix);
103 void *Addr = Dylib->getAddressOfSymbol(Tmp.c_str());
104 if (!Addr && KV.second == SymbolLookupFlags::RequiredSymbol) {
105 // FIXME: Collect all failing symbols before erroring out.
106 SymbolNameVector MissingSymbols;
107 MissingSymbols.push_back(Sym);
108 return make_error<SymbolsNotFound>(SSP, std::move(MissingSymbols));
109 }
110 R.back().push_back(pointerToJITTargetAddress(Addr));
111 }
112 }
113
114 return R;
115}
116
117Expected<int32_t>
118SelfExecutorProcessControl::runAsMain(ExecutorAddr MainFnAddr,
119 ArrayRef<std::string> Args) {
120 using MainTy = int (*)(int, char *[]);
121 return orc::runAsMain(MainFnAddr.toPtr<MainTy>(), Args);
122}
123
124Expected<int32_t>
125SelfExecutorProcessControl::runAsVoidFunction(ExecutorAddr VoidFnAddr) {
126 using VoidTy = int (*)();
127 return orc::runAsVoidFunction(VoidFnAddr.toPtr<VoidTy>());
128}
129
130Expected<int32_t>
131SelfExecutorProcessControl::runAsIntFunction(ExecutorAddr IntFnAddr, int Arg) {
132 using IntTy = int (*)(int);
133 return orc::runAsIntFunction(IntFnAddr.toPtr<IntTy>(), Arg);
134}
135
136void SelfExecutorProcessControl::callWrapperAsync(ExecutorAddr WrapperFnAddr,
137 IncomingWFRHandler SendResult,
138 ArrayRef<char> ArgBuffer) {
139 using WrapperFnTy =
140 shared::CWrapperFunctionResult (*)(const char *Data, size_t Size);
141 auto *WrapperFn = WrapperFnAddr.toPtr<WrapperFnTy>();
142 SendResult(WrapperFn(ArgBuffer.data(), ArgBuffer.size()));
143}
144
145Error SelfExecutorProcessControl::disconnect() {
146 D->shutdown();
147 return Error::success();
148}
149
150void SelfExecutorProcessControl::writeUInt8sAsync(
151 ArrayRef<tpctypes::UInt8Write> Ws, WriteResultFn OnWriteComplete) {
152 for (auto &W : Ws)
153 *W.Addr.toPtr<uint8_t *>() = W.Value;
154 OnWriteComplete(Error::success());
155}
156
157void SelfExecutorProcessControl::writeUInt16sAsync(
158 ArrayRef<tpctypes::UInt16Write> Ws, WriteResultFn OnWriteComplete) {
159 for (auto &W : Ws)
160 *W.Addr.toPtr<uint16_t *>() = W.Value;
161 OnWriteComplete(Error::success());
162}
163
164void SelfExecutorProcessControl::writeUInt32sAsync(
165 ArrayRef<tpctypes::UInt32Write> Ws, WriteResultFn OnWriteComplete) {
166 for (auto &W : Ws)
167 *W.Addr.toPtr<uint32_t *>() = W.Value;
168 OnWriteComplete(Error::success());
169}
170
171void SelfExecutorProcessControl::writeUInt64sAsync(
172 ArrayRef<tpctypes::UInt64Write> Ws, WriteResultFn OnWriteComplete) {
173 for (auto &W : Ws)
174 *W.Addr.toPtr<uint64_t *>() = W.Value;
175 OnWriteComplete(Error::success());
176}
177
178void SelfExecutorProcessControl::writeBuffersAsync(
179 ArrayRef<tpctypes::BufferWrite> Ws, WriteResultFn OnWriteComplete) {
180 for (auto &W : Ws)
181 memcpy(W.Addr.toPtr<char *>(), W.Buffer.data(), W.Buffer.size());
182 OnWriteComplete(Error::success());
183}
184
185shared::CWrapperFunctionResult
186SelfExecutorProcessControl::jitDispatchViaWrapperFunctionManager(
187 void *Ctx, const void *FnTag, const char *Data, size_t Size) {
188
189 LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("orc")) { { dbgs() << "jit-dispatch call with tag " <<
FnTag << " and " << Size << " byte payload.\n"
; }; } } while (false)
1
Assuming 'DebugFlag' is false
2
Loop condition is false. Exiting loop
190 dbgs() << "jit-dispatch call with tag " << FnTag << " and " << Sizedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("orc")) { { dbgs() << "jit-dispatch call with tag " <<
FnTag << " and " << Size << " byte payload.\n"
; }; } } while (false)
191 << " byte payload.\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("orc")) { { dbgs() << "jit-dispatch call with tag " <<
FnTag << " and " << Size << " byte payload.\n"
; }; } } while (false)
192 })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("orc")) { { dbgs() << "jit-dispatch call with tag " <<
FnTag << " and " << Size << " byte payload.\n"
; }; } } while (false)
;
193
194 std::promise<shared::WrapperFunctionResult> ResultP;
3
Calling default constructor for 'promise<llvm::orc::shared::WrapperFunctionResult>'
5
Returning from default constructor for 'promise<llvm::orc::shared::WrapperFunctionResult>'
195 auto ResultF = ResultP.get_future();
196 static_cast<SelfExecutorProcessControl *>(Ctx)
197 ->getExecutionSession()
198 .runJITDispatchHandler(
199 [ResultP = std::move(ResultP)](
6
Potential leak of memory pointed to by field '_M_head_impl'
200 shared::WrapperFunctionResult Result) mutable {
201 ResultP.set_value(std::move(Result));
202 },
203 pointerToJITTargetAddress(FnTag), {Data, Size});
204
205 return ResultF.get().release();
206}
207
208} // end namespace orc
209} // end namespace llvm

/usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/future

1// <future> -*- C++ -*-
2
3// Copyright (C) 2009-2020 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library. This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file include/future
26 * This is a Standard C++ Library header.
27 */
28
29#ifndef _GLIBCXX_FUTURE1
30#define _GLIBCXX_FUTURE1 1
31
32#pragma GCC system_header
33
34#if __cplusplus201703L < 201103L
35# include <bits/c++0x_warning.h>
36#else
37
38#include <mutex>
39#include <thread>
40#include <condition_variable>
41#include <system_error>
42#include <atomic>
43#include <bits/atomic_futex.h>
44#include <bits/functexcept.h>
45#include <bits/invoke.h>
46#include <bits/unique_ptr.h>
47#include <bits/shared_ptr.h>
48#include <bits/std_function.h>
49#include <bits/uses_allocator.h>
50#include <bits/allocated_ptr.h>
51#include <ext/aligned_buffer.h>
52
53namespace std _GLIBCXX_VISIBILITY(default)__attribute__ ((__visibility__ ("default")))
54{
55_GLIBCXX_BEGIN_NAMESPACE_VERSION
56
57 /**
58 * @defgroup futures Futures
59 * @ingroup concurrency
60 *
61 * Classes for futures support.
62 * @{
63 */
64
65 /// Error code for futures
66 enum class future_errc
67 {
68 future_already_retrieved = 1,
69 promise_already_satisfied,
70 no_state,
71 broken_promise
72 };
73
74 /// Specialization.
75 template<>
76 struct is_error_code_enum<future_errc> : public true_type { };
77
78 /// Points to a statically-allocated object derived from error_category.
79 const error_category&
80 future_category() noexcept;
81
82 /// Overload for make_error_code.
83 inline error_code
84 make_error_code(future_errc __errc) noexcept
85 { return error_code(static_cast<int>(__errc), future_category()); }
86
87 /// Overload for make_error_condition.
88 inline error_condition
89 make_error_condition(future_errc __errc) noexcept
90 { return error_condition(static_cast<int>(__errc), future_category()); }
91
92 /**
93 * @brief Exception type thrown by futures.
94 * @ingroup exceptions
95 */
96 class future_error : public logic_error
97 {
98 public:
99 explicit
100 future_error(future_errc __errc)
101 : future_error(std::make_error_code(__errc))
102 { }
103
104 virtual ~future_error() noexcept;
105
106 virtual const char*
107 what() const noexcept;
108
109 const error_code&
110 code() const noexcept { return _M_code; }
111
112 private:
113 explicit
114 future_error(error_code __ec)
115 : logic_error("std::future_error: " + __ec.message()), _M_code(__ec)
116 { }
117
118 friend void __throw_future_error(int);
119
120 error_code _M_code;
121 };
122
123 // Forward declarations.
124 template<typename _Res>
125 class future;
126
127 template<typename _Res>
128 class shared_future;
129
130 template<typename _Signature>
131 class packaged_task;
132
133 template<typename _Res>
134 class promise;
135
136 /// Launch code for futures
137 enum class launch
138 {
139 async = 1,
140 deferred = 2
141 };
142
143 constexpr launch operator&(launch __x, launch __y)
144 {
145 return static_cast<launch>(
146 static_cast<int>(__x) & static_cast<int>(__y));
147 }
148
149 constexpr launch operator|(launch __x, launch __y)
150 {
151 return static_cast<launch>(
152 static_cast<int>(__x) | static_cast<int>(__y));
153 }
154
155 constexpr launch operator^(launch __x, launch __y)
156 {
157 return static_cast<launch>(
158 static_cast<int>(__x) ^ static_cast<int>(__y));
159 }
160
161 constexpr launch operator~(launch __x)
162 { return static_cast<launch>(~static_cast<int>(__x)); }
163
164 inline launch& operator&=(launch& __x, launch __y)
165 { return __x = __x & __y; }
166
167 inline launch& operator|=(launch& __x, launch __y)
168 { return __x = __x | __y; }
169
170 inline launch& operator^=(launch& __x, launch __y)
171 { return __x = __x ^ __y; }
172
173 /// Status code for futures
174 enum class future_status
175 {
176 ready,
177 timeout,
178 deferred
179 };
180
181 // _GLIBCXX_RESOLVE_LIB_DEFECTS
182 // 2021. Further incorrect usages of result_of
183 template<typename _Fn, typename... _Args>
184 using __async_result_of = typename __invoke_result<
185 typename decay<_Fn>::type, typename decay<_Args>::type...>::type;
186
187 template<typename _Fn, typename... _Args>
188 future<__async_result_of<_Fn, _Args...>>
189 async(launch __policy, _Fn&& __fn, _Args&&... __args);
190
191 template<typename _Fn, typename... _Args>
192 future<__async_result_of<_Fn, _Args...>>
193 async(_Fn&& __fn, _Args&&... __args);
194
195#if defined(_GLIBCXX_HAS_GTHREADS1)
196
197 /// Base class and enclosing scope.
198 struct __future_base
199 {
200 /// Base class for results.
201 struct _Result_base
202 {
203 exception_ptr _M_error;
204
205 _Result_base(const _Result_base&) = delete;
206 _Result_base& operator=(const _Result_base&) = delete;
207
208 // _M_destroy() allows derived classes to control deallocation
209 virtual void _M_destroy() = 0;
210
211 struct _Deleter
212 {
213 void operator()(_Result_base* __fr) const { __fr->_M_destroy(); }
214 };
215
216 protected:
217 _Result_base();
218 virtual ~_Result_base();
219 };
220
221 /// A unique_ptr for result objects.
222 template<typename _Res>
223 using _Ptr = unique_ptr<_Res, _Result_base::_Deleter>;
224
225 /// A result object that has storage for an object of type _Res.
226 template<typename _Res>
227 struct _Result : _Result_base
228 {
229 private:
230 __gnu_cxx::__aligned_buffer<_Res> _M_storage;
231 bool _M_initialized;
232
233 public:
234 typedef _Res result_type;
235
236 _Result() noexcept : _M_initialized() { }
237
238 ~_Result()
239 {
240 if (_M_initialized)
241 _M_value().~_Res();
242 }
243
244 // Return lvalue, future will add const or rvalue-reference
245 _Res&
246 _M_value() noexcept { return *_M_storage._M_ptr(); }
247
248 void
249 _M_set(const _Res& __res)
250 {
251 ::new (_M_storage._M_addr()) _Res(__res);
252 _M_initialized = true;
253 }
254
255 void
256 _M_set(_Res&& __res)
257 {
258 ::new (_M_storage._M_addr()) _Res(std::move(__res));
259 _M_initialized = true;
260 }
261
262 private:
263 void _M_destroy() { delete this; }
264 };
265
266 /// A result object that uses an allocator.
267 template<typename _Res, typename _Alloc>
268 struct _Result_alloc final : _Result<_Res>, _Alloc
269 {
270 using __allocator_type = __alloc_rebind<_Alloc, _Result_alloc>;
271
272 explicit
273 _Result_alloc(const _Alloc& __a) : _Result<_Res>(), _Alloc(__a)
274 { }
275
276 private:
277 void _M_destroy()
278 {
279 __allocator_type __a(*this);
280 __allocated_ptr<__allocator_type> __guard_ptr{ __a, this };
281 this->~_Result_alloc();
282 }
283 };
284
285 // Create a result object that uses an allocator.
286 template<typename _Res, typename _Allocator>
287 static _Ptr<_Result_alloc<_Res, _Allocator>>
288 _S_allocate_result(const _Allocator& __a)
289 {
290 using __result_type = _Result_alloc<_Res, _Allocator>;
291 typename __result_type::__allocator_type __a2(__a);
292 auto __guard = std::__allocate_guarded(__a2);
293 __result_type* __p = ::new((void*)__guard.get()) __result_type{__a};
294 __guard = nullptr;
295 return _Ptr<__result_type>(__p);
296 }
297
298 // Keep it simple for std::allocator.
299 template<typename _Res, typename _Tp>
300 static _Ptr<_Result<_Res>>
301 _S_allocate_result(const std::allocator<_Tp>& __a)
302 {
303 return _Ptr<_Result<_Res>>(new _Result<_Res>);
304 }
305
306 // Base class for various types of shared state created by an
307 // asynchronous provider (such as a std::promise) and shared with one
308 // or more associated futures.
309 class _State_baseV2
310 {
311 typedef _Ptr<_Result_base> _Ptr_type;
312
313 enum _Status : unsigned {
314 __not_ready,
315 __ready
316 };
317
318 _Ptr_type _M_result;
319 __atomic_futex_unsigned<> _M_status;
320 atomic_flag _M_retrieved = ATOMIC_FLAG_INIT{ 0 };
321 once_flag _M_once;
322
323 public:
324 _State_baseV2() noexcept : _M_result(), _M_status(_Status::__not_ready)
325 { }
326 _State_baseV2(const _State_baseV2&) = delete;
327 _State_baseV2& operator=(const _State_baseV2&) = delete;
328 virtual ~_State_baseV2() = default;
329
330 _Result_base&
331 wait()
332 {
333 // Run any deferred function or join any asynchronous thread:
334 _M_complete_async();
335 // Acquire MO makes sure this synchronizes with the thread that made
336 // the future ready.
337 _M_status._M_load_when_equal(_Status::__ready, memory_order_acquire);
338 return *_M_result;
339 }
340
341 template<typename _Rep, typename _Period>
342 future_status
343 wait_for(const chrono::duration<_Rep, _Period>& __rel)
344 {
345 // First, check if the future has been made ready. Use acquire MO
346 // to synchronize with the thread that made it ready.
347 if (_M_status._M_load(memory_order_acquire) == _Status::__ready)
348 return future_status::ready;
349
350 if (_M_is_deferred_future())
351 return future_status::deferred;
352
353 // Don't wait unless the relative time is greater than zero.
354 if (__rel > __rel.zero()
355 && _M_status._M_load_when_equal_for(_Status::__ready,
356 memory_order_acquire,
357 __rel))
358 {
359 // _GLIBCXX_RESOLVE_LIB_DEFECTS
360 // 2100. timed waiting functions must also join
361 // This call is a no-op by default except on an async future,
362 // in which case the async thread is joined. It's also not a
363 // no-op for a deferred future, but such a future will never
364 // reach this point because it returns future_status::deferred
365 // instead of waiting for the future to become ready (see
366 // above). Async futures synchronize in this call, so we need
367 // no further synchronization here.
368 _M_complete_async();
369
370 return future_status::ready;
371 }
372 return future_status::timeout;
373 }
374
375 template<typename _Clock, typename _Duration>
376 future_status
377 wait_until(const chrono::time_point<_Clock, _Duration>& __abs)
378 {
379#if __cplusplus201703L > 201703L
380 static_assert(chrono::is_clock_v<_Clock>);
381#endif
382 // First, check if the future has been made ready. Use acquire MO
383 // to synchronize with the thread that made it ready.
384 if (_M_status._M_load(memory_order_acquire) == _Status::__ready)
385 return future_status::ready;
386
387 if (_M_is_deferred_future())
388 return future_status::deferred;
389
390 if (_M_status._M_load_when_equal_until(_Status::__ready,
391 memory_order_acquire,
392 __abs))
393 {
394 // _GLIBCXX_RESOLVE_LIB_DEFECTS
395 // 2100. timed waiting functions must also join
396 // See wait_for(...) above.
397 _M_complete_async();
398
399 return future_status::ready;
400 }
401 return future_status::timeout;
402 }
403
404 // Provide a result to the shared state and make it ready.
405 // Calls at most once: _M_result = __res();
406 void
407 _M_set_result(function<_Ptr_type()> __res, bool __ignore_failure = false)
408 {
409 bool __did_set = false;
410 // all calls to this function are serialized,
411 // side-effects of invoking __res only happen once
412 call_once(_M_once, &_State_baseV2::_M_do_set, this,
413 std::__addressof(__res), std::__addressof(__did_set));
414 if (__did_set)
415 // Use release MO to synchronize with observers of the ready state.
416 _M_status._M_store_notify_all(_Status::__ready,
417 memory_order_release);
418 else if (!__ignore_failure)
419 __throw_future_error(int(future_errc::promise_already_satisfied));
420 }
421
422 // Provide a result to the shared state but delay making it ready
423 // until the calling thread exits.
424 // Calls at most once: _M_result = __res();
425 void
426 _M_set_delayed_result(function<_Ptr_type()> __res,
427 weak_ptr<_State_baseV2> __self)
428 {
429 bool __did_set = false;
430 unique_ptr<_Make_ready> __mr{new _Make_ready};
431 // all calls to this function are serialized,
432 // side-effects of invoking __res only happen once
433 call_once(_M_once, &_State_baseV2::_M_do_set, this,
434 std::__addressof(__res), std::__addressof(__did_set));
435 if (!__did_set)
436 __throw_future_error(int(future_errc::promise_already_satisfied));
437 __mr->_M_shared_state = std::move(__self);
438 __mr->_M_set();
439 __mr.release();
440 }
441
442 // Abandon this shared state.
443 void
444 _M_break_promise(_Ptr_type __res)
445 {
446 if (static_cast<bool>(__res))
447 {
448 __res->_M_error =
449 make_exception_ptr(future_error(future_errc::broken_promise));
450 // This function is only called when the last asynchronous result
451 // provider is abandoning this shared state, so noone can be
452 // trying to make the shared state ready at the same time, and
453 // we can access _M_result directly instead of through call_once.
454 _M_result.swap(__res);
455 // Use release MO to synchronize with observers of the ready state.
456 _M_status._M_store_notify_all(_Status::__ready,
457 memory_order_release);
458 }
459 }
460
461 // Called when this object is first passed to a future.
462 void
463 _M_set_retrieved_flag()
464 {
465 if (_M_retrieved.test_and_set())
466 __throw_future_error(int(future_errc::future_already_retrieved));
467 }
468
469 template<typename _Res, typename _Arg>
470 struct _Setter;
471
472 // set lvalues
473 template<typename _Res, typename _Arg>
474 struct _Setter<_Res, _Arg&>
475 {
476 // check this is only used by promise<R>::set_value(const R&)
477 // or promise<R&>::set_value(R&)
478 static_assert(is_same<_Res, _Arg&>::value // promise<R&>
479 || is_same<const _Res, _Arg>::value, // promise<R>
480 "Invalid specialisation");
481
482 // Used by std::promise to copy construct the result.
483 typename promise<_Res>::_Ptr_type operator()() const
484 {
485 _M_promise->_M_storage->_M_set(*_M_arg);
486 return std::move(_M_promise->_M_storage);
487 }
488 promise<_Res>* _M_promise;
489 _Arg* _M_arg;
490 };
491
492 // set rvalues
493 template<typename _Res>
494 struct _Setter<_Res, _Res&&>
495 {
496 // Used by std::promise to move construct the result.
497 typename promise<_Res>::_Ptr_type operator()() const
498 {
499 _M_promise->_M_storage->_M_set(std::move(*_M_arg));
500 return std::move(_M_promise->_M_storage);
501 }
502 promise<_Res>* _M_promise;
503 _Res* _M_arg;
504 };
505
506 // set void
507 template<typename _Res>
508 struct _Setter<_Res, void>
509 {
510 static_assert(is_void<_Res>::value, "Only used for promise<void>");
511
512 typename promise<_Res>::_Ptr_type operator()() const
513 { return std::move(_M_promise->_M_storage); }
514
515 promise<_Res>* _M_promise;
516 };
517
518 struct __exception_ptr_tag { };
519
520 // set exceptions
521 template<typename _Res>
522 struct _Setter<_Res, __exception_ptr_tag>
523 {
524 // Used by std::promise to store an exception as the result.
525 typename promise<_Res>::_Ptr_type operator()() const
526 {
527 _M_promise->_M_storage->_M_error = *_M_ex;
528 return std::move(_M_promise->_M_storage);
529 }
530
531 promise<_Res>* _M_promise;
532 exception_ptr* _M_ex;
533 };
534
535 template<typename _Res, typename _Arg>
536 static _Setter<_Res, _Arg&&>
537 __setter(promise<_Res>* __prom, _Arg&& __arg)
538 {
539 _S_check(__prom->_M_future);
540 return _Setter<_Res, _Arg&&>{ __prom, std::__addressof(__arg) };
541 }
542
543 template<typename _Res>
544 static _Setter<_Res, __exception_ptr_tag>
545 __setter(exception_ptr& __ex, promise<_Res>* __prom)
546 {
547 _S_check(__prom->_M_future);
548 return _Setter<_Res, __exception_ptr_tag>{ __prom, &__ex };
549 }
550
551 template<typename _Res>
552 static _Setter<_Res, void>
553 __setter(promise<_Res>* __prom)
554 {
555 _S_check(__prom->_M_future);
556 return _Setter<_Res, void>{ __prom };
557 }
558
559 template<typename _Tp>
560 static void
561 _S_check(const shared_ptr<_Tp>& __p)
562 {
563 if (!static_cast<bool>(__p))
564 __throw_future_error((int)future_errc::no_state);
565 }
566
567 private:
568 // The function invoked with std::call_once(_M_once, ...).
569 void
570 _M_do_set(function<_Ptr_type()>* __f, bool* __did_set)
571 {
572 _Ptr_type __res = (*__f)();
573 // Notify the caller that we did try to set; if we do not throw an
574 // exception, the caller will be aware that it did set (e.g., see
575 // _M_set_result).
576 *__did_set = true;
577 _M_result.swap(__res); // nothrow
578 }
579
580 // Wait for completion of async function.
581 virtual void _M_complete_async() { }
582
583 // Return true if state corresponds to a deferred function.
584 virtual bool _M_is_deferred_future() const { return false; }
585
586 struct _Make_ready final : __at_thread_exit_elt
587 {
588 weak_ptr<_State_baseV2> _M_shared_state;
589 static void _S_run(void*);
590 void _M_set();
591 };
592 };
593
594#ifdef _GLIBCXX_ASYNC_ABI_COMPAT
595 class _State_base;
596 class _Async_state_common;
597#else
598 using _State_base = _State_baseV2;
599 class _Async_state_commonV2;
600#endif
601
602 template<typename _BoundFn,
603 typename _Res = decltype(std::declval<_BoundFn&>()())>
604 class _Deferred_state;
605
606 template<typename _BoundFn,
607 typename _Res = decltype(std::declval<_BoundFn&>()())>
608 class _Async_state_impl;
609
610 template<typename _Signature>
611 class _Task_state_base;
612
613 template<typename _Fn, typename _Alloc, typename _Signature>
614 class _Task_state;
615
616 template<typename _BoundFn>
617 static std::shared_ptr<_State_base>
618 _S_make_deferred_state(_BoundFn&& __fn);
619
620 template<typename _BoundFn>
621 static std::shared_ptr<_State_base>
622 _S_make_async_state(_BoundFn&& __fn);
623
624 template<typename _Res_ptr, typename _Fn,
625 typename _Res = typename _Res_ptr::element_type::result_type>
626 struct _Task_setter;
627
628 template<typename _Res_ptr, typename _BoundFn>
629 static _Task_setter<_Res_ptr, _BoundFn>
630 _S_task_setter(_Res_ptr& __ptr, _BoundFn& __call)
631 {
632 return { std::__addressof(__ptr), std::__addressof(__call) };
633 }
634 };
635
636 /// Partial specialization for reference types.
637 template<typename _Res>
638 struct __future_base::_Result<_Res&> : __future_base::_Result_base
639 {
640 typedef _Res& result_type;
641
642 _Result() noexcept : _M_value_ptr() { }
643
644 void
645 _M_set(_Res& __res) noexcept
646 { _M_value_ptr = std::addressof(__res); }
647
648 _Res& _M_get() noexcept { return *_M_value_ptr; }
649
650 private:
651 _Res* _M_value_ptr;
652
653 void _M_destroy() { delete this; }
654 };
655
656 /// Explicit specialization for void.
657 template<>
658 struct __future_base::_Result<void> : __future_base::_Result_base
659 {
660 typedef void result_type;
661
662 private:
663 void _M_destroy() { delete this; }
664 };
665
666#ifndef _GLIBCXX_ASYNC_ABI_COMPAT
667
668 // Allow _Setter objects to be stored locally in std::function
669 template<typename _Res, typename _Arg>
670 struct __is_location_invariant
671 <__future_base::_State_base::_Setter<_Res, _Arg>>
672 : true_type { };
673
674 // Allow _Task_setter objects to be stored locally in std::function
675 template<typename _Res_ptr, typename _Fn, typename _Res>
676 struct __is_location_invariant
677 <__future_base::_Task_setter<_Res_ptr, _Fn, _Res>>
678 : true_type { };
679
680 /// Common implementation for future and shared_future.
681 template<typename _Res>
682 class __basic_future : public __future_base
683 {
684 protected:
685 typedef shared_ptr<_State_base> __state_type;
686 typedef __future_base::_Result<_Res>& __result_type;
687
688 private:
689 __state_type _M_state;
690
691 public:
692 // Disable copying.
693 __basic_future(const __basic_future&) = delete;
694 __basic_future& operator=(const __basic_future&) = delete;
695
696 bool
697 valid() const noexcept { return static_cast<bool>(_M_state); }
698
699 void
700 wait() const
701 {
702 _State_base::_S_check(_M_state);
703 _M_state->wait();
704 }
705
706 template<typename _Rep, typename _Period>
707 future_status
708 wait_for(const chrono::duration<_Rep, _Period>& __rel) const
709 {
710 _State_base::_S_check(_M_state);
711 return _M_state->wait_for(__rel);
712 }
713
714 template<typename _Clock, typename _Duration>
715 future_status
716 wait_until(const chrono::time_point<_Clock, _Duration>& __abs) const
717 {
718 _State_base::_S_check(_M_state);
719 return _M_state->wait_until(__abs);
720 }
721
722 protected:
723 /// Wait for the state to be ready and rethrow any stored exception
724 __result_type
725 _M_get_result() const
726 {
727 _State_base::_S_check(_M_state);
728 _Result_base& __res = _M_state->wait();
729 if (!(__res._M_error == 0))
730 rethrow_exception(__res._M_error);
731 return static_cast<__result_type>(__res);
732 }
733
734 void _M_swap(__basic_future& __that) noexcept
735 {
736 _M_state.swap(__that._M_state);
737 }
738
739 // Construction of a future by promise::get_future()
740 explicit
741 __basic_future(const __state_type& __state) : _M_state(__state)
742 {
743 _State_base::_S_check(_M_state);
744 _M_state->_M_set_retrieved_flag();
745 }
746
747 // Copy construction from a shared_future
748 explicit
749 __basic_future(const shared_future<_Res>&) noexcept;
750
751 // Move construction from a shared_future
752 explicit
753 __basic_future(shared_future<_Res>&&) noexcept;
754
755 // Move construction from a future
756 explicit
757 __basic_future(future<_Res>&&) noexcept;
758
759 constexpr __basic_future() noexcept : _M_state() { }
760
761 struct _Reset
762 {
763 explicit _Reset(__basic_future& __fut) noexcept : _M_fut(__fut) { }
764 ~_Reset() { _M_fut._M_state.reset(); }
765 __basic_future& _M_fut;
766 };
767 };
768
769
770 /// Primary template for future.
771 template<typename _Res>
772 class future : public __basic_future<_Res>
773 {
774 friend class promise<_Res>;
775 template<typename> friend class packaged_task;
776 template<typename _Fn, typename... _Args>
777 friend future<__async_result_of<_Fn, _Args...>>
778 async(launch, _Fn&&, _Args&&...);
779
780 typedef __basic_future<_Res> _Base_type;
781 typedef typename _Base_type::__state_type __state_type;
782
783 explicit
784 future(const __state_type& __state) : _Base_type(__state) { }
785
786 public:
787 constexpr future() noexcept : _Base_type() { }
788
789 /// Move constructor
790 future(future&& __uf) noexcept : _Base_type(std::move(__uf)) { }
791
792 // Disable copying
793 future(const future&) = delete;
794 future& operator=(const future&) = delete;
795
796 future& operator=(future&& __fut) noexcept
797 {
798 future(std::move(__fut))._M_swap(*this);
799 return *this;
800 }
801
802 /// Retrieving the value
803 _Res
804 get()
805 {
806 typename _Base_type::_Reset __reset(*this);
807 return std::move(this->_M_get_result()._M_value());
808 }
809
810 shared_future<_Res> share() noexcept;
811 };
812
813 /// Partial specialization for future<R&>
814 template<typename _Res>
815 class future<_Res&> : public __basic_future<_Res&>
816 {
817 friend class promise<_Res&>;
818 template<typename> friend class packaged_task;
819 template<typename _Fn, typename... _Args>
820 friend future<__async_result_of<_Fn, _Args...>>
821 async(launch, _Fn&&, _Args&&...);
822
823 typedef __basic_future<_Res&> _Base_type;
824 typedef typename _Base_type::__state_type __state_type;
825
826 explicit
827 future(const __state_type& __state) : _Base_type(__state) { }
828
829 public:
830 constexpr future() noexcept : _Base_type() { }
831
832 /// Move constructor
833 future(future&& __uf) noexcept : _Base_type(std::move(__uf)) { }
834
835 // Disable copying
836 future(const future&) = delete;
837 future& operator=(const future&) = delete;
838
839 future& operator=(future&& __fut) noexcept
840 {
841 future(std::move(__fut))._M_swap(*this);
842 return *this;
843 }
844
845 /// Retrieving the value
846 _Res&
847 get()
848 {
849 typename _Base_type::_Reset __reset(*this);
850 return this->_M_get_result()._M_get();
851 }
852
853 shared_future<_Res&> share() noexcept;
854 };
855
856 /// Explicit specialization for future<void>
857 template<>
858 class future<void> : public __basic_future<void>
859 {
860 friend class promise<void>;
861 template<typename> friend class packaged_task;
862 template<typename _Fn, typename... _Args>
863 friend future<__async_result_of<_Fn, _Args...>>
864 async(launch, _Fn&&, _Args&&...);
865
866 typedef __basic_future<void> _Base_type;
867 typedef typename _Base_type::__state_type __state_type;
868
869 explicit
870 future(const __state_type& __state) : _Base_type(__state) { }
871
872 public:
873 constexpr future() noexcept : _Base_type() { }
874
875 /// Move constructor
876 future(future&& __uf) noexcept : _Base_type(std::move(__uf)) { }
877
878 // Disable copying
879 future(const future&) = delete;
880 future& operator=(const future&) = delete;
881
882 future& operator=(future&& __fut) noexcept
883 {
884 future(std::move(__fut))._M_swap(*this);
885 return *this;
886 }
887
888 /// Retrieving the value
889 void
890 get()
891 {
892 typename _Base_type::_Reset __reset(*this);
893 this->_M_get_result();
894 }
895
896 shared_future<void> share() noexcept;
897 };
898
899
900 /// Primary template for shared_future.
901 template<typename _Res>
902 class shared_future : public __basic_future<_Res>
903 {
904 typedef __basic_future<_Res> _Base_type;
905
906 public:
907 constexpr shared_future() noexcept : _Base_type() { }
908
909 /// Copy constructor
910 shared_future(const shared_future& __sf) noexcept : _Base_type(__sf) { }
911
912 /// Construct from a future rvalue
913 shared_future(future<_Res>&& __uf) noexcept
914 : _Base_type(std::move(__uf))
915 { }
916
917 /// Construct from a shared_future rvalue
918 shared_future(shared_future&& __sf) noexcept
919 : _Base_type(std::move(__sf))
920 { }
921
922 shared_future& operator=(const shared_future& __sf) noexcept
923 {
924 shared_future(__sf)._M_swap(*this);
925 return *this;
926 }
927
928 shared_future& operator=(shared_future&& __sf) noexcept
929 {
930 shared_future(std::move(__sf))._M_swap(*this);
931 return *this;
932 }
933
934 /// Retrieving the value
935 const _Res&
936 get() const { return this->_M_get_result()._M_value(); }
937 };
938
939 /// Partial specialization for shared_future<R&>
940 template<typename _Res>
941 class shared_future<_Res&> : public __basic_future<_Res&>
942 {
943 typedef __basic_future<_Res&> _Base_type;
944
945 public:
946 constexpr shared_future() noexcept : _Base_type() { }
947
948 /// Copy constructor
949 shared_future(const shared_future& __sf) : _Base_type(__sf) { }
950
951 /// Construct from a future rvalue
952 shared_future(future<_Res&>&& __uf) noexcept
953 : _Base_type(std::move(__uf))
954 { }
955
956 /// Construct from a shared_future rvalue
957 shared_future(shared_future&& __sf) noexcept
958 : _Base_type(std::move(__sf))
959 { }
960
961 shared_future& operator=(const shared_future& __sf)
962 {
963 shared_future(__sf)._M_swap(*this);
964 return *this;
965 }
966
967 shared_future& operator=(shared_future&& __sf) noexcept
968 {
969 shared_future(std::move(__sf))._M_swap(*this);
970 return *this;
971 }
972
973 /// Retrieving the value
974 _Res&
975 get() const { return this->_M_get_result()._M_get(); }
976 };
977
978 /// Explicit specialization for shared_future<void>
979 template<>
980 class shared_future<void> : public __basic_future<void>
981 {
982 typedef __basic_future<void> _Base_type;
983
984 public:
985 constexpr shared_future() noexcept : _Base_type() { }
986
987 /// Copy constructor
988 shared_future(const shared_future& __sf) : _Base_type(__sf) { }
989
990 /// Construct from a future rvalue
991 shared_future(future<void>&& __uf) noexcept
992 : _Base_type(std::move(__uf))
993 { }
994
995 /// Construct from a shared_future rvalue
996 shared_future(shared_future&& __sf) noexcept
997 : _Base_type(std::move(__sf))
998 { }
999
1000 shared_future& operator=(const shared_future& __sf)
1001 {
1002 shared_future(__sf)._M_swap(*this);
1003 return *this;
1004 }
1005
1006 shared_future& operator=(shared_future&& __sf) noexcept
1007 {
1008 shared_future(std::move(__sf))._M_swap(*this);
1009 return *this;
1010 }
1011
1012 // Retrieving the value
1013 void
1014 get() const { this->_M_get_result(); }
1015 };
1016
1017 // Now we can define the protected __basic_future constructors.
1018 template<typename _Res>
1019 inline __basic_future<_Res>::
1020 __basic_future(const shared_future<_Res>& __sf) noexcept
1021 : _M_state(__sf._M_state)
1022 { }
1023
1024 template<typename _Res>
1025 inline __basic_future<_Res>::
1026 __basic_future(shared_future<_Res>&& __sf) noexcept
1027 : _M_state(std::move(__sf._M_state))
1028 { }
1029
1030 template<typename _Res>
1031 inline __basic_future<_Res>::
1032 __basic_future(future<_Res>&& __uf) noexcept
1033 : _M_state(std::move(__uf._M_state))
1034 { }
1035
1036 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1037 // 2556. Wide contract for future::share()
1038 template<typename _Res>
1039 inline shared_future<_Res>
1040 future<_Res>::share() noexcept
1041 { return shared_future<_Res>(std::move(*this)); }
1042
1043 template<typename _Res>
1044 inline shared_future<_Res&>
1045 future<_Res&>::share() noexcept
1046 { return shared_future<_Res&>(std::move(*this)); }
1047
1048 inline shared_future<void>
1049 future<void>::share() noexcept
1050 { return shared_future<void>(std::move(*this)); }
1051
1052 /// Primary template for promise
1053 template<typename _Res>
1054 class promise
1055 {
1056 typedef __future_base::_State_base _State;
1057 typedef __future_base::_Result<_Res> _Res_type;
1058 typedef __future_base::_Ptr<_Res_type> _Ptr_type;
1059 template<typename, typename> friend class _State::_Setter;
1060 friend _State;
1061
1062 shared_ptr<_State> _M_future;
1063 _Ptr_type _M_storage;
1064
1065 public:
1066 promise()
1067 : _M_future(std::make_shared<_State>()),
1068 _M_storage(new _Res_type())
4
Memory is allocated
1069 { }
1070
1071 promise(promise&& __rhs) noexcept
1072 : _M_future(std::move(__rhs._M_future)),
1073 _M_storage(std::move(__rhs._M_storage))
1074 { }
1075
1076 template<typename _Allocator>
1077 promise(allocator_arg_t, const _Allocator& __a)
1078 : _M_future(std::allocate_shared<_State>(__a)),
1079 _M_storage(__future_base::_S_allocate_result<_Res>(__a))
1080 { }
1081
1082 template<typename _Allocator>
1083 promise(allocator_arg_t, const _Allocator&, promise&& __rhs)
1084 : _M_future(std::move(__rhs._M_future)),
1085 _M_storage(std::move(__rhs._M_storage))
1086 { }
1087
1088 promise(const promise&) = delete;
1089
1090 ~promise()
1091 {
1092 if (static_cast<bool>(_M_future) && !_M_future.unique())
1093 _M_future->_M_break_promise(std::move(_M_storage));
1094 }
1095
1096 // Assignment
1097 promise&
1098 operator=(promise&& __rhs) noexcept
1099 {
1100 promise(std::move(__rhs)).swap(*this);
1101 return *this;
1102 }
1103
1104 promise& operator=(const promise&) = delete;
1105
1106 void
1107 swap(promise& __rhs) noexcept
1108 {
1109 _M_future.swap(__rhs._M_future);
1110 _M_storage.swap(__rhs._M_storage);
1111 }
1112
1113 // Retrieving the result
1114 future<_Res>
1115 get_future()
1116 { return future<_Res>(_M_future); }
1117
1118 // Setting the result
1119 void
1120 set_value(const _Res& __r)
1121 { _M_future->_M_set_result(_State::__setter(this, __r)); }
1122
1123 void
1124 set_value(_Res&& __r)
1125 { _M_future->_M_set_result(_State::__setter(this, std::move(__r))); }
1126
1127 void
1128 set_exception(exception_ptr __p)
1129 { _M_future->_M_set_result(_State::__setter(__p, this)); }
1130
1131 void
1132 set_value_at_thread_exit(const _Res& __r)
1133 {
1134 _M_future->_M_set_delayed_result(_State::__setter(this, __r),
1135 _M_future);
1136 }
1137
1138 void
1139 set_value_at_thread_exit(_Res&& __r)
1140 {
1141 _M_future->_M_set_delayed_result(
1142 _State::__setter(this, std::move(__r)), _M_future);
1143 }
1144
1145 void
1146 set_exception_at_thread_exit(exception_ptr __p)
1147 {
1148 _M_future->_M_set_delayed_result(_State::__setter(__p, this),
1149 _M_future);
1150 }
1151 };
1152
1153 template<typename _Res>
1154 inline void
1155 swap(promise<_Res>& __x, promise<_Res>& __y) noexcept
1156 { __x.swap(__y); }
1157
1158 template<typename _Res, typename _Alloc>
1159 struct uses_allocator<promise<_Res>, _Alloc>
1160 : public true_type { };
1161
1162
1163 /// Partial specialization for promise<R&>
1164 template<typename _Res>
1165 class promise<_Res&>
1166 {
1167 typedef __future_base::_State_base _State;
1168 typedef __future_base::_Result<_Res&> _Res_type;
1169 typedef __future_base::_Ptr<_Res_type> _Ptr_type;
1170 template<typename, typename> friend class _State::_Setter;
1171 friend _State;
1172
1173 shared_ptr<_State> _M_future;
1174 _Ptr_type _M_storage;
1175
1176 public:
1177 promise()
1178 : _M_future(std::make_shared<_State>()),
1179 _M_storage(new _Res_type())
1180 { }
1181
1182 promise(promise&& __rhs) noexcept
1183 : _M_future(std::move(__rhs._M_future)),
1184 _M_storage(std::move(__rhs._M_storage))
1185 { }
1186
1187 template<typename _Allocator>
1188 promise(allocator_arg_t, const _Allocator& __a)
1189 : _M_future(std::allocate_shared<_State>(__a)),
1190 _M_storage(__future_base::_S_allocate_result<_Res&>(__a))
1191 { }
1192
1193 template<typename _Allocator>
1194 promise(allocator_arg_t, const _Allocator&, promise&& __rhs)
1195 : _M_future(std::move(__rhs._M_future)),
1196 _M_storage(std::move(__rhs._M_storage))
1197 { }
1198
1199 promise(const promise&) = delete;
1200
1201 ~promise()
1202 {
1203 if (static_cast<bool>(_M_future) && !_M_future.unique())
1204 _M_future->_M_break_promise(std::move(_M_storage));
1205 }
1206
1207 // Assignment
1208 promise&
1209 operator=(promise&& __rhs) noexcept
1210 {
1211 promise(std::move(__rhs)).swap(*this);
1212 return *this;
1213 }
1214
1215 promise& operator=(const promise&) = delete;
1216
1217 void
1218 swap(promise& __rhs) noexcept
1219 {
1220 _M_future.swap(__rhs._M_future);
1221 _M_storage.swap(__rhs._M_storage);
1222 }
1223
1224 // Retrieving the result
1225 future<_Res&>
1226 get_future()
1227 { return future<_Res&>(_M_future); }
1228
1229 // Setting the result
1230 void
1231 set_value(_Res& __r)
1232 { _M_future->_M_set_result(_State::__setter(this, __r)); }
1233
1234 void
1235 set_exception(exception_ptr __p)
1236 { _M_future->_M_set_result(_State::__setter(__p, this)); }
1237
1238 void
1239 set_value_at_thread_exit(_Res& __r)
1240 {
1241 _M_future->_M_set_delayed_result(_State::__setter(this, __r),
1242 _M_future);
1243 }
1244
1245 void
1246 set_exception_at_thread_exit(exception_ptr __p)
1247 {
1248 _M_future->_M_set_delayed_result(_State::__setter(__p, this),
1249 _M_future);
1250 }
1251 };
1252
1253 /// Explicit specialization for promise<void>
1254 template<>
1255 class promise<void>
1256 {
1257 typedef __future_base::_State_base _State;
1258 typedef __future_base::_Result<void> _Res_type;
1259 typedef __future_base::_Ptr<_Res_type> _Ptr_type;
1260 template<typename, typename> friend class _State::_Setter;
1261 friend _State;
1262
1263 shared_ptr<_State> _M_future;
1264 _Ptr_type _M_storage;
1265
1266 public:
1267 promise()
1268 : _M_future(std::make_shared<_State>()),
1269 _M_storage(new _Res_type())
1270 { }
1271
1272 promise(promise&& __rhs) noexcept
1273 : _M_future(std::move(__rhs._M_future)),
1274 _M_storage(std::move(__rhs._M_storage))
1275 { }
1276
1277 template<typename _Allocator>
1278 promise(allocator_arg_t, const _Allocator& __a)
1279 : _M_future(std::allocate_shared<_State>(__a)),
1280 _M_storage(__future_base::_S_allocate_result<void>(__a))
1281 { }
1282
1283 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1284 // 2095. missing constructors needed for uses-allocator construction
1285 template<typename _Allocator>
1286 promise(allocator_arg_t, const _Allocator&, promise&& __rhs)
1287 : _M_future(std::move(__rhs._M_future)),
1288 _M_storage(std::move(__rhs._M_storage))
1289 { }
1290
1291 promise(const promise&) = delete;
1292
1293 ~promise()
1294 {
1295 if (static_cast<bool>(_M_future) && !_M_future.unique())
1296 _M_future->_M_break_promise(std::move(_M_storage));
1297 }
1298
1299 // Assignment
1300 promise&
1301 operator=(promise&& __rhs) noexcept
1302 {
1303 promise(std::move(__rhs)).swap(*this);
1304 return *this;
1305 }
1306
1307 promise& operator=(const promise&) = delete;
1308
1309 void
1310 swap(promise& __rhs) noexcept
1311 {
1312 _M_future.swap(__rhs._M_future);
1313 _M_storage.swap(__rhs._M_storage);
1314 }
1315
1316 // Retrieving the result
1317 future<void>
1318 get_future()
1319 { return future<void>(_M_future); }
1320
1321 // Setting the result
1322 void
1323 set_value()
1324 { _M_future->_M_set_result(_State::__setter(this)); }
1325
1326 void
1327 set_exception(exception_ptr __p)
1328 { _M_future->_M_set_result(_State::__setter(__p, this)); }
1329
1330 void
1331 set_value_at_thread_exit()
1332 { _M_future->_M_set_delayed_result(_State::__setter(this), _M_future); }
1333
1334 void
1335 set_exception_at_thread_exit(exception_ptr __p)
1336 {
1337 _M_future->_M_set_delayed_result(_State::__setter(__p, this),
1338 _M_future);
1339 }
1340 };
1341
1342 template<typename _Ptr_type, typename _Fn, typename _Res>
1343 struct __future_base::_Task_setter
1344 {
1345 // Invoke the function and provide the result to the caller.
1346 _Ptr_type operator()() const
1347 {
1348 __tryif (true)
1349 {
1350 (*_M_result)->_M_set((*_M_fn)());
1351 }
1352 __catch(const __cxxabiv1::__forced_unwind&)if (false)
1353 {
1354 __throw_exception_again; // will cause broken_promise
1355 }
1356 __catch(...)if (false)
1357 {
1358 (*_M_result)->_M_error = current_exception();
1359 }
1360 return std::move(*_M_result);
1361 }
1362 _Ptr_type* _M_result;
1363 _Fn* _M_fn;
1364 };
1365
1366 template<typename _Ptr_type, typename _Fn>
1367 struct __future_base::_Task_setter<_Ptr_type, _Fn, void>
1368 {
1369 _Ptr_type operator()() const
1370 {
1371 __tryif (true)
1372 {
1373 (*_M_fn)();
1374 }
1375 __catch(const __cxxabiv1::__forced_unwind&)if (false)
1376 {
1377 __throw_exception_again; // will cause broken_promise
1378 }
1379 __catch(...)if (false)
1380 {
1381 (*_M_result)->_M_error = current_exception();
1382 }
1383 return std::move(*_M_result);
1384 }
1385 _Ptr_type* _M_result;
1386 _Fn* _M_fn;
1387 };
1388
1389 // Holds storage for a packaged_task's result.
1390 template<typename _Res, typename... _Args>
1391 struct __future_base::_Task_state_base<_Res(_Args...)>
1392 : __future_base::_State_base
1393 {
1394 typedef _Res _Res_type;
1395
1396 template<typename _Alloc>
1397 _Task_state_base(const _Alloc& __a)
1398 : _M_result(_S_allocate_result<_Res>(__a))
1399 { }
1400
1401 // Invoke the stored task and make the state ready.
1402 virtual void
1403 _M_run(_Args&&... __args) = 0;
1404
1405 // Invoke the stored task and make the state ready at thread exit.
1406 virtual void
1407 _M_run_delayed(_Args&&... __args, weak_ptr<_State_base>) = 0;
1408
1409 virtual shared_ptr<_Task_state_base>
1410 _M_reset() = 0;
1411
1412 typedef __future_base::_Ptr<_Result<_Res>> _Ptr_type;
1413 _Ptr_type _M_result;
1414 };
1415
1416 // Holds a packaged_task's stored task.
1417 template<typename _Fn, typename _Alloc, typename _Res, typename... _Args>
1418 struct __future_base::_Task_state<_Fn, _Alloc, _Res(_Args...)> final
1419 : __future_base::_Task_state_base<_Res(_Args...)>
1420 {
1421 template<typename _Fn2>
1422 _Task_state(_Fn2&& __fn, const _Alloc& __a)
1423 : _Task_state_base<_Res(_Args...)>(__a),
1424 _M_impl(std::forward<_Fn2>(__fn), __a)
1425 { }
1426
1427 private:
1428 virtual void
1429 _M_run(_Args&&... __args)
1430 {
1431 auto __boundfn = [&] () -> _Res {
1432 return std::__invoke_r<_Res>(_M_impl._M_fn,
1433 std::forward<_Args>(__args)...);
1434 };
1435 this->_M_set_result(_S_task_setter(this->_M_result, __boundfn));
1436 }
1437
1438 virtual void
1439 _M_run_delayed(_Args&&... __args, weak_ptr<_State_base> __self)
1440 {
1441 auto __boundfn = [&] () -> _Res {
1442 return std::__invoke_r<_Res>(_M_impl._M_fn,
1443 std::forward<_Args>(__args)...);
1444 };
1445 this->_M_set_delayed_result(_S_task_setter(this->_M_result, __boundfn),
1446 std::move(__self));
1447 }
1448
1449 virtual shared_ptr<_Task_state_base<_Res(_Args...)>>
1450 _M_reset();
1451
1452 struct _Impl : _Alloc
1453 {
1454 template<typename _Fn2>
1455 _Impl(_Fn2&& __fn, const _Alloc& __a)
1456 : _Alloc(__a), _M_fn(std::forward<_Fn2>(__fn)) { }
1457 _Fn _M_fn;
1458 } _M_impl;
1459 };
1460
1461 template<typename _Signature, typename _Fn,
1462 typename _Alloc = std::allocator<int>>
1463 static shared_ptr<__future_base::_Task_state_base<_Signature>>
1464 __create_task_state(_Fn&& __fn, const _Alloc& __a = _Alloc())
1465 {
1466 typedef typename decay<_Fn>::type _Fn2;
1467 typedef __future_base::_Task_state<_Fn2, _Alloc, _Signature> _State;
1468 return std::allocate_shared<_State>(__a, std::forward<_Fn>(__fn), __a);
1469 }
1470
1471 template<typename _Fn, typename _Alloc, typename _Res, typename... _Args>
1472 shared_ptr<__future_base::_Task_state_base<_Res(_Args...)>>
1473 __future_base::_Task_state<_Fn, _Alloc, _Res(_Args...)>::_M_reset()
1474 {
1475 return __create_task_state<_Res(_Args...)>(std::move(_M_impl._M_fn),
1476 static_cast<_Alloc&>(_M_impl));
1477 }
1478
1479 /// packaged_task
1480 template<typename _Res, typename... _ArgTypes>
1481 class packaged_task<_Res(_ArgTypes...)>
1482 {
1483 typedef __future_base::_Task_state_base<_Res(_ArgTypes...)> _State_type;
1484 shared_ptr<_State_type> _M_state;
1485
1486 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1487 // 3039. Unnecessary decay in thread and packaged_task
1488 template<typename _Fn, typename _Fn2 = __remove_cvref_t<_Fn>>
1489 using __not_same
1490 = typename enable_if<!is_same<packaged_task, _Fn2>::value>::type;
1491
1492 public:
1493 // Construction and destruction
1494 packaged_task() noexcept { }
1495
1496 template<typename _Fn, typename = __not_same<_Fn>>
1497 explicit
1498 packaged_task(_Fn&& __fn)
1499 : _M_state(
1500 __create_task_state<_Res(_ArgTypes...)>(std::forward<_Fn>(__fn)))
1501 { }
1502
1503#if __cplusplus201703L < 201703L
1504 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1505 // 2097. packaged_task constructors should be constrained
1506 // 2407. [this constructor should not be] explicit
1507 // 2921. packaged_task and type-erased allocators
1508 template<typename _Fn, typename _Alloc, typename = __not_same<_Fn>>
1509 packaged_task(allocator_arg_t, const _Alloc& __a, _Fn&& __fn)
1510 : _M_state(__create_task_state<_Res(_ArgTypes...)>(
1511 std::forward<_Fn>(__fn), __a))
1512 { }
1513
1514 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1515 // 2095. missing constructors needed for uses-allocator construction
1516 template<typename _Allocator>
1517 packaged_task(allocator_arg_t, const _Allocator& __a) noexcept
1518 { }
1519
1520 template<typename _Allocator>
1521 packaged_task(allocator_arg_t, const _Allocator&,
1522 const packaged_task&) = delete;
1523
1524 template<typename _Allocator>
1525 packaged_task(allocator_arg_t, const _Allocator&,
1526 packaged_task&& __other) noexcept
1527 { this->swap(__other); }
1528#endif
1529
1530 ~packaged_task()
1531 {
1532 if (static_cast<bool>(_M_state) && !_M_state.unique())
1533 _M_state->_M_break_promise(std::move(_M_state->_M_result));
1534 }
1535
1536 // No copy
1537 packaged_task(const packaged_task&) = delete;
1538 packaged_task& operator=(const packaged_task&) = delete;
1539
1540 // Move support
1541 packaged_task(packaged_task&& __other) noexcept
1542 { this->swap(__other); }
1543
1544 packaged_task& operator=(packaged_task&& __other) noexcept
1545 {
1546 packaged_task(std::move(__other)).swap(*this);
1547 return *this;
1548 }
1549
1550 void
1551 swap(packaged_task& __other) noexcept
1552 { _M_state.swap(__other._M_state); }
1553
1554 bool
1555 valid() const noexcept
1556 { return static_cast<bool>(_M_state); }
1557
1558 // Result retrieval
1559 future<_Res>
1560 get_future()
1561 { return future<_Res>(_M_state); }
1562
1563 // Execution
1564 void
1565 operator()(_ArgTypes... __args)
1566 {
1567 __future_base::_State_base::_S_check(_M_state);
1568 _M_state->_M_run(std::forward<_ArgTypes>(__args)...);
1569 }
1570
1571 void
1572 make_ready_at_thread_exit(_ArgTypes... __args)
1573 {
1574 __future_base::_State_base::_S_check(_M_state);
1575 _M_state->_M_run_delayed(std::forward<_ArgTypes>(__args)..., _M_state);
1576 }
1577
1578 void
1579 reset()
1580 {
1581 __future_base::_State_base::_S_check(_M_state);
1582 packaged_task __tmp;
1583 __tmp._M_state = _M_state;
1584 _M_state = _M_state->_M_reset();
1585 }
1586 };
1587
1588 /// swap
1589 template<typename _Res, typename... _ArgTypes>
1590 inline void
1591 swap(packaged_task<_Res(_ArgTypes...)>& __x,
1592 packaged_task<_Res(_ArgTypes...)>& __y) noexcept
1593 { __x.swap(__y); }
1594
1595#if __cplusplus201703L < 201703L
1596 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1597 // 2976. Dangling uses_allocator specialization for packaged_task
1598 template<typename _Res, typename _Alloc>
1599 struct uses_allocator<packaged_task<_Res>, _Alloc>
1600 : public true_type { };
1601#endif
1602
1603 // Shared state created by std::async().
1604 // Holds a deferred function and storage for its result.
1605 template<typename _BoundFn, typename _Res>
1606 class __future_base::_Deferred_state final
1607 : public __future_base::_State_base
1608 {
1609 public:
1610 explicit
1611 _Deferred_state(_BoundFn&& __fn)
1612 : _M_result(new _Result<_Res>()), _M_fn(std::move(__fn))
1613 { }
1614
1615 private:
1616 typedef __future_base::_Ptr<_Result<_Res>> _Ptr_type;
1617 _Ptr_type _M_result;
1618 _BoundFn _M_fn;
1619
1620 // Run the deferred function.
1621 virtual void
1622 _M_complete_async()
1623 {
1624 // Multiple threads can call a waiting function on the future and
1625 // reach this point at the same time. The call_once in _M_set_result
1626 // ensures only the first one run the deferred function, stores the
1627 // result in _M_result, swaps that with the base _M_result and makes
1628 // the state ready. Tell _M_set_result to ignore failure so all later
1629 // calls do nothing.
1630 _M_set_result(_S_task_setter(_M_result, _M_fn), true);
1631 }
1632
1633 // Caller should check whether the state is ready first, because this
1634 // function will return true even after the deferred function has run.
1635 virtual bool _M_is_deferred_future() const { return true; }
1636 };
1637
1638 // Common functionality hoisted out of the _Async_state_impl template.
1639 class __future_base::_Async_state_commonV2
1640 : public __future_base::_State_base
1641 {
1642 protected:
1643 ~_Async_state_commonV2() = default;
1644
1645 // Make waiting functions block until the thread completes, as if joined.
1646 //
1647 // This function is used by wait() to satisfy the first requirement below
1648 // and by wait_for() / wait_until() to satisfy the second.
1649 //
1650 // [futures.async]:
1651 //
1652 // - a call to a waiting function on an asynchronous return object that
1653 // shares the shared state created by this async call shall block until
1654 // the associated thread has completed, as if joined, or else time out.
1655 //
1656 // - the associated thread completion synchronizes with the return from
1657 // the first function that successfully detects the ready status of the
1658 // shared state or with the return from the last function that releases
1659 // the shared state, whichever happens first.
1660 virtual void _M_complete_async() { _M_join(); }
1661
1662 void _M_join() { std::call_once(_M_once, &thread::join, &_M_thread); }
1663
1664 thread _M_thread;
1665 once_flag _M_once;
1666 };
1667
1668 // Shared state created by std::async().
1669 // Starts a new thread that runs a function and makes the shared state ready.
1670 template<typename _BoundFn, typename _Res>
1671 class __future_base::_Async_state_impl final
1672 : public __future_base::_Async_state_commonV2
1673 {
1674 public:
1675 explicit
1676 _Async_state_impl(_BoundFn&& __fn)
1677 : _M_result(new _Result<_Res>()), _M_fn(std::move(__fn))
1678 {
1679 _M_thread = std::thread{ [this] {
1680 __tryif (true)
1681 {
1682 _M_set_result(_S_task_setter(_M_result, _M_fn));
1683 }
1684 __catch (const __cxxabiv1::__forced_unwind&)if (false)
1685 {
1686 // make the shared state ready on thread cancellation
1687 if (static_cast<bool>(_M_result))
1688 this->_M_break_promise(std::move(_M_result));
1689 __throw_exception_again;
1690 }
1691 } };
1692 }
1693
1694 // Must not destroy _M_result and _M_fn until the thread finishes.
1695 // Call join() directly rather than through _M_join() because no other
1696 // thread can be referring to this state if it is being destroyed.
1697 ~_Async_state_impl() { if (_M_thread.joinable()) _M_thread.join(); }
1698
1699 private:
1700 typedef __future_base::_Ptr<_Result<_Res>> _Ptr_type;
1701 _Ptr_type _M_result;
1702 _BoundFn _M_fn;
1703 };
1704
1705 template<typename _BoundFn>
1706 inline std::shared_ptr<__future_base::_State_base>
1707 __future_base::_S_make_deferred_state(_BoundFn&& __fn)
1708 {
1709 typedef typename remove_reference<_BoundFn>::type __fn_type;
1710 typedef _Deferred_state<__fn_type> __state_type;
1711 return std::make_shared<__state_type>(std::move(__fn));
1712 }
1713
1714 template<typename _BoundFn>
1715 inline std::shared_ptr<__future_base::_State_base>
1716 __future_base::_S_make_async_state(_BoundFn&& __fn)
1717 {
1718 typedef typename remove_reference<_BoundFn>::type __fn_type;
1719 typedef _Async_state_impl<__fn_type> __state_type;
1720 return std::make_shared<__state_type>(std::move(__fn));
1721 }
1722
1723
1724 /// async
1725 template<typename _Fn, typename... _Args>
1726 _GLIBCXX_NODISCARD[[__nodiscard__]] future<__async_result_of<_Fn, _Args...>>
1727 async(launch __policy, _Fn&& __fn, _Args&&... __args)
1728 {
1729 std::shared_ptr<__future_base::_State_base> __state;
1730 if ((__policy & launch::async) == launch::async)
1731 {
1732 __tryif (true)
1733 {
1734 __state = __future_base::_S_make_async_state(
1735 std::thread::__make_invoker(std::forward<_Fn>(__fn),
1736 std::forward<_Args>(__args)...)
1737 );
1738 }
1739#if __cpp_exceptions
1740 catch(const system_error& __e)
1741 {
1742 if (__e.code() != errc::resource_unavailable_try_again
1743 || (__policy & launch::deferred) != launch::deferred)
1744 throw;
1745 }
1746#endif
1747 }
1748 if (!__state)
1749 {
1750 __state = __future_base::_S_make_deferred_state(
1751 std::thread::__make_invoker(std::forward<_Fn>(__fn),
1752 std::forward<_Args>(__args)...));
1753 }
1754 return future<__async_result_of<_Fn, _Args...>>(__state);
1755 }
1756
1757 /// async, potential overload
1758 template<typename _Fn, typename... _Args>
1759 _GLIBCXX_NODISCARD[[__nodiscard__]] inline future<__async_result_of<_Fn, _Args...>>
1760 async(_Fn&& __fn, _Args&&... __args)
1761 {
1762 return std::async(launch::async|launch::deferred,
1763 std::forward<_Fn>(__fn),
1764 std::forward<_Args>(__args)...);
1765 }
1766
1767#endif // _GLIBCXX_ASYNC_ABI_COMPAT
1768#endif // _GLIBCXX_HAS_GTHREADS
1769
1770 // @} group futures
1771_GLIBCXX_END_NAMESPACE_VERSION
1772} // namespace
1773
1774#endif // C++11
1775
1776#endif // _GLIBCXX_FUTURE