您可以找到程序here
我正在消息传递框架0MQ中构建一个程序。我尝试实施我在here
中发布的内容使用g++ -std=c++11 test.cpp -o test -lzmq -lpthread
编译的程序。
要运行程序,请传递一个参数作为您想要的线程号。然后将该参数分配给变量worker_num
。
在主线程中,我使用以下命令设置线程:
vector<thread> pool;
for(int i = 0; i < worker_num; i++)
{
cout << "main() : creating thread, " << i << endl;
pool.push_back(thread(task1, (void *)&context, i));
}
我想确保在主线程向其分配作业之前,所有工作线程都已成功连接到主线程。
while(true)
{
if(sync_done)
{
cout << "sync done in main thread" << endl;
break;
}
zmq::message_t sync_msg(4);
memcpy((void *)sync_msg.data(), SYNC_MSG, SYNC_MSGLEN);
for(int i = 0; i < worker_num; i++)
distask_socket.send(sync_msg);
for(int i = 0; i < worker_num; i++)
{
if(sync_done)
break;
if(i != 0)
this_thread::sleep_for(chrono::milliseconds(500));
zmq::message_t res_msg;
int ret = getres_socket.recv(&res_msg, ZMQ_DONTWAIT);
if(ret == -1 && errno == EAGAIN)
continue;
int threadID = stoi(string((char *)res_msg.data()));
sync_done = if_sync_done(threadID, sync_array, worker_num);
}
}
所以主线程的作用是:每次将带有PUSH端点的sync
msgs的#worker_num推送到工作线程,然后从其PULL端点读取确认消息。如果主线程检索确认消息的#worker_num,则完成同步。来自worker的同步消息的格式是:字符串中的工作线程ID。因此,线程0会将字符串中的0
传递回主线程。
但是运行我的程序:
$ ./test 1
main() : creating thread, 0
thread id:0
thread 0 receives: sync
thread 0 sends: 0
thread 0 sync done
main thread receives sync msg from thread 1 # you may get many copies of this msg
terminate called after throwing an instance of 'std::invalid_argument'
what(): stoi
Aborted
main thread receives sync msg from thread 1
表示线程是2线程创建的:线程0和线程1.知道为什么?我确实传递了1
作为参数。注意,如果你自己运行程序,你可能会获得其他输出。
计划已更新:here。
最后我发现了什么是错的。
预期输出,您会看到线程0将0
传递给主线程以通知已完成同步:
$ ./test 1
input parameter is: 1
main() : creating thread, 0
thread 0 receives: sync
to_string 0
thread 0 sends: 0, with size: 1
thread 0 sync done
pass 0 to if_sync_done
main thread receives sync msg from thread 0
sync done in main thread
意外输出,您会看到不可打印的字符传递给 stoi()
:
$ ./test 1
input parameter is: 1
main() : creating thread, 0
thread 0 receives: sync
to_string 0
thread 0 sends: 0, with size: 1
thread 0 sync done
pass to if_sync_done # !!!!!
terminate called after throwing an instance of 'std::invalid_argument'
what(): stoi
Aborted
所以我似乎错误地使用了message_t
。所以我需要确保在主线程将内容传递给stoi()
之前,缓冲区仍然存在。
我会自己添加一个答案。