以下代码有什么问题？运行时,程序以未知异常中止
#include <iostream>
#include <future>
int main() {
auto promise = std::promise<int>{};
auto future_one = promise.get_future();
promise.set_value(1);
return 0;
}
terminate called after throwing an instance of 'std::system_error' what(): Unknown error -1 Aborted (core dumped)
g – 版本给我
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.
相同的代码在mac上运行得很好
注意异常源自的代码行是promise.set_value(1)
解决方法
简而言之,添加-pthread可以解决您的问题.
$g++ -std=c++14 -g -pthread -o temp temp.cpp $./temp
细节
我可以在编译时使用以下命令重现Ubuntu 16.04上的行为：
$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转储显示：
(gdb) bt #0 0x00007ffff74ab428 in __GI_raise (sig=sig@entry=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,bool*>(std::once_flag&,void (std::__future_base::_State_baseV2::*&&)(std::function<std::unique_ptr<std::__future_base::_Result_base,std::__future_base::_State_baseV2*&&,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,DIE 0xeb8a>) at /usr/include/c++/5/future:1075 #10 0x0000000000401759 in main () at temp.cpp:7
从转储中,我们可以看到它正在使用互斥锁等.
然后我意识到std :: future的东西依赖于线程,所以它需要链接到pthread,否则我们会看到这个异常.
对于std :: thread也一样
