以下代碼有什麼問題？當運行程序與未知異常中止來自std :: promise的未知異常

#include <iostream> 
#include <future> 

int main() { 
    auto promise = std::promise<int>{}; 
    auto future_one = promise.get_future(); 
    promise.set_value(1); 

    return 0; 
}

錯誤輸出

g++ --version我給

g++ (Ubuntu 5.4.0-6ubuntu1~16.04.2) 5.4.0 20160609 
Copyright (C) 2015 Free Software Foundation, Inc. 
This is free software; see the source for copying conditions. There is NO 
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

相同的代碼工作就好在Mac

注意的代碼行異常來源於是promise.set_value(1)

來源

2017-05-12 Curious

@ vu1p3n0x空的共享狀態不應暗示未來get_future將拋出。另外它的set_value拋出這裏由於某種原因.. – Curious

把一個調試器的東西，並找出什麼是拋出異常。代碼沒有問題，我無法在Wandbox的GCC 5.4上重現報告的異常。 –

總之，加入-pthread解決您的問題。

$ g++ -std=c++14 -g -pthread -o temp temp.cpp 
$ ./temp

詳細

我可以編譯下面的命令複製在Ubuntu 16.04的行爲：

$ g++ -std=c++14 -g -o temp temp.cpp 
$ ./temp 
terminate called after throwing an instance of 'std::system_error' 
    what(): Unknown error -1 
Aborted (core dumped)

GDB轉儲顯示：

(gdb) bt 
#0 0x00007ffff74ab428 in __GI_raise ([email protected]=6) at ../sysdeps/unix/sysv/linux/raise.c:54 
#1 0x00007ffff74ad02a in __GI_abort() at abort.c:89 
#2 0x00007ffff7ae484d in __gnu_cxx::__verbose_terminate_handler()() from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 
#3 0x00007ffff7ae26b6 in ??() from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 
#4 0x00007ffff7ae2701 in std::terminate()() from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 
#5 0x00007ffff7ae2919 in __cxa_throw() from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 
#6 0x00007ffff7b0b7fe in std::__throw_system_error(int)() from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 
#7 0x000000000040259b in std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter>()>*, bool*), std::__future_base::_State_baseV2*, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter>()>*, bool*>(std::once_flag&, void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter>()>*, bool*), std::__future_base::_State_baseV2*&&, std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter>()>*&&, bool*&&) (__once=..., 
    __f=<unknown type in /home/mine/tempdir/temp, CU 0x0, DIE 0xe578>) at /usr/include/c++/5/mutex:746 
#8 0x0000000000401e06 in std::__future_base::_State_baseV2::_M_set_result(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter>()>, bool) (this=0x61ac30, __res=..., __ignore_failure=false) at /usr/include/c++/5/future:387 
#9 0x0000000000402aee in std::promise<int>::set_value(int&&) (this=0x7fffffffe1c0, __r=<unknown type in /home/mine/tempdir/temp, CU 0x0, DIE 0xeb8a>) at /usr/include/c++/5/future:1075 
#10 0x0000000000401759 in main() at temp.cpp:7

從轉儲，我們可以看到它使用靜音x等然後我意識到std::future東西取決於線程，所以它需要鏈接到pthread，否則我們看到這個異常。

同爲std::thread

來源

2017-05-12 05:23:30 Mine

哇，我應該記住你需要在許多系統上使用'-pthread'標誌 – Curious

來自std :: promise的未知異常

回答

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