próbuję programu:Ilość async/futures w C++ 11
#include <iostream>
#include <thread>
#include <future>
int foo() {
return 0;
}
int main(int argc, char* argv[]) {
for (auto i = 0L; i < 10000; ++i) {
auto f = std::async(foo);
f.get();
}
return 0;
}
Compiler VS11 x64.
Budowa:
cl /EHsc /Zi async.cpp && async
Dla mnie to awarie programu. Podejrzewam, że istnieje limit liczby fizycznych kontraktów futures w tym samym czasie. Jeśli zmniejszę liczbę iteracji do kilku zamówień, to działa.
Więc dwa pytania:
Czy istnieje limit faktycznie uruchomionych futures w C++ 11?
Dlaczego ten kod w ogóle się zawiesza? Jeśli jawnie zrobię "get()" zaraz po "async()", to musi on ukończyć przyszłość przed kolejną iteracją, co oznacza, że tylko jedna przyszłość biegnie jednocześnie.
UPDATE
mam uproszczony kod do:
#include <future>
int main(int argc, char* argv[]) {
for (auto i = 0L; i < 1000000; ++i) {
auto f = std::async([](){ return 0; });
f.get();
}
return 0;
}
i nadal wywala mnie. Nie rzuca, sprawdziłem to. Ale teraz mam widoczny ślad stosu:
async.exe!_Mtx_unlock(_Mtx_internal_imp_t * * mtx) Line 229 C++
async.exe!std::_Mtx_unlockX(_Mtx_internal_imp_t * * _Mtx) Line 84 C++
async.exe!std::_Mutex_base::unlock() Line 47 C++
async.exe!std::unique_lock<std::mutex>::~unique_lock<std::mutex>() Line 284 C++
async.exe!std::_Associated_state<int>::_Set_value(int && _Val, bool _At_thread_exit) Line 358 C++
async.exe!std::_Packaged_state<int __cdecl(void)>::_Call_immediate() Line 569 C++
async.exe!std::_Async_state<int>::`std::U_Nil::ain::ain'::`3'::<lambda_A200A86DFF9A63A1>::operator()() Line 700 C++
[email protected]@[email protected]<lambda_A200A86DFF9A63A1>@[email protected][email protected]<lambda_23AC5A2FBB53FD4D>@[email protected][email protected]@@[email protected]@[email protected]@[email protected]@@[email protected]@@[email protected]@[email protected]@[email protected][email protected][email protected]<lambda_23AC5A2FBB53FD4D>@[email protected][email protected]@@[email protected]@[email protected]@[email protected]@@[email protected]@[email protected][email protected]@[email protected]@QEAAXXZ() Line 420 C++
[email protected][email protected][email protected]<lambda_A200A86DFF9A63A1>@[email protected][email protected]<lambda_23AC5A2FBB53FD4D>@[email protected][email protected]@@[email protected]@[email protected]@[email protected]@@[email protected]@@[email protected]@[email protected]@[email protected][email protected][email protected]<lambda_23AC5A2FBB53FD4D>@[email protected][email protected]@@[email protected]@[email protected]@[email protected]@@[email protected]@[email protected][email protected]@[email protected]@[email protected][email protected][email protected]@@[email protected]@[email protected]@[email protected]@@[email protected]@@[email protected][email protected]@[email protected]@[email protected]@[email protected]@@[email protected]@UEAAXXZ() Line 217 C++
async.exe!std::_Func_class<void,std::_Nil,std::_Nil,std::_Nil,std::_Nil,std::_Nil,std::_Nil,std::_Nil>::operator()() Line 486 C++
async.exe!`Concurrency::details::_MakeVoidToUnitFunc'::`3'::<lambda_25D33530A43E1C90>::operator()() Line 1056 C++
async.exe!std::_Callable_obj<`Concurrency::details::_MakeVoidToUnitFunc'::`3'::<lambda_25D33530A43E1C90>,0>::_ApplyX<Concurrency::details::_Unit_type>() Line 420 C++
async.exe!std::_Func_impl<std::_Callable_obj<`Concurrency::details::_MakeVoidToUnitFunc'::`3'::<lambda_25D33530A43E1C90>,0>,std::allocator<std::_Func_class<Concurrency::details::_Unit_type,std::_Nil,std::_Nil,std::_Nil,std::_Nil,std::_Nil,std::_Nil,std::_Nil> >,Concurrency::details::_Unit_type,std::_Nil,std::_Nil,std::_Nil,std::_Nil,std::_Nil,std::_Nil,std::_Nil>::_Do_call() Line 217 C++
async.exe!std::_Func_class<Concurrency::details::_Unit_type,std::_Nil,std::_Nil,std::_Nil,std::_Nil,std::_Nil,std::_Nil,std::_Nil>::operator()() Line 486 C++
async.exe!`Concurrency::details::_Task_impl<Concurrency::details::_Unit_type>::_ScheduleTask'::`3'::<lambda_7D9BCD859405C05B>::operator()() Line 325 C++
async.exe!Concurrency::details::_PPLTaskHandle<`Concurrency::details::_Task_impl<Concurrency::details::_Unit_type>::_ScheduleTask'::`3'::<lambda_7D9BCD859405C05B> >::operator()() Line 72 C++
async.exe!Concurrency::details::_UnrealizedChore::_InvokeBridge<Concurrency::details::_PPLTaskHandle<`Concurrency::details::_Task_impl<Concurrency::details::_Unit_type>::_ScheduleTask'::`3'::<lambda_7D9BCD859405C05B> > >(Concurrency::details::_PPLTaskHandle<`Concurrency::details::_Task_impl<Concurrency::details::_Unit_type>::_ScheduleTask'::`3'::<lambda_7D9BCD859405C05B> > * _PChore) Line 4190 C++
async.exe!Concurrency::details::_UnrealizedChore::_UnstructuredChoreWrapper(Concurrency::details::_UnrealizedChore * pChore) Line 275 C++
async.exe!Concurrency::details::_PPLTaskChore::_DeletingChoreWrapper(Concurrency::details::_UnrealizedChore * pChore) Line 78 C++
async.exe!Concurrency::details::InternalContextBase::ExecuteChoreInline(Concurrency::details::WorkItem * pWork) Line 1600 C++
async.exe!Concurrency::details::InternalContextBase::Dispatch(Concurrency::DispatchState * pDispatchState) Line 1704 C++
async.exe!Concurrency::details::FreeThreadProxy::Dispatch() Line 191 C++
async.exe!Concurrency::details::ThreadProxy::ThreadProxyMain(void * lpParameter) Line 173 C++
kernel32.dll!0000000076df652d() Unknown
ntdll.dll!0000000076f2c521() Unknown
i wątków:
Unflagged 1864 0 Worker Thread ntdll.dll thread ntdll.dll!0000000076f518ca Normal
Unflagged 10964 0 Main Thread Main Thread async.exe!do_signal Normal
Unflagged 7436 0 Worker Thread ntdll.dll thread ntdll.dll!0000000076f52c1a Normal
Unflagged 10232 0 Worker Thread async.exe!Concurrency::details::ThreadProxy::ThreadProxyMain async.exe!Concurrency::details::ThreadProxy::SuspendExecution Normal
Unflagged > 10624 0 Worker Thread async.exe!Concurrency::details::ThreadProxy::ThreadProxyMain async.exe!_Mtx_unlock Normal
Unflagged 4756 0 Worker Thread async.exe!Concurrency::details::ThreadProxy::ThreadProxyMain async.exe!Concurrency::details::ThreadProxy::SuspendExecution Normal
Unflagged 11100 0 Worker Thread async.exe!Concurrency::details::ThreadProxy::ThreadProxyMain async.exe!Concurrency::details::InternalContextBase::WaitForWork Normal
Unflagged 6440 0 Worker Thread async.exe!Concurrency::details::ThreadProxy::ThreadProxyMain async.exe!std::vector<std::pair<void (__cdecl*)(void * __ptr64),void * __ptr64>,std::allocator<std::pair<void (__cdecl*)(void * __ptr64),void * __ptr64> > >::_Tidy Normal
używam VS 11.0.40825.2 PREREL.
Brzmi jak błąd kompilatora. –
Nie wierzę, że ta inwokacja uruchamia inny wątek, jest to tylko opóźnione wykonanie. Np. Foo powinno zostać wywołane, gdy wykonywana jest linia f.get(). – alanxz
Debugger powinien pomóc ci zrozumieć, dlaczego kod ulega awarii. Spróbuję tego, zanim założę, że kompilator jest zepsuty. –