經常提到你可以銷燬zmq上下文,任何共享這個上下文的東西都會退出,但是這會產生一個噩夢,因爲這會刪除套接字對象,你現有的代碼必須盡最大努力避免一個雷區死指針。
試圖關閉套接字不起作用,或者是因爲它們不是線程安全的,最終會導致崩潰。
答案:最好的方法是按照ZeroMQ指南的建議,通過多線程進行任何使用;使用zmq套接字而不是線程互斥/鎖/等。
Requester::Requester(zmq::context_t* context)
{
m_context = context;
// Create a socket that you'll use as the interrupt-event receiver
// I'm using a random address and an inproc socket (inprocs need to share a context)
snprintf(m_signalStopAddr, sizeof(m_signalStopAddr)/sizeof(*m_signalStopAddr), "inproc://%lx%x", (unsigned long)this, rand());
m_signalStop = new zmq::socket_t(m_context, ZMQ_PAIR);
m_signalStop->bind(m_signalStopAddr);
}
// Your thread-safe poll interrupter
Requester::interrupt()
{
char dummy;
zmq::socket_t doSignal(m_context, ZMQ_PAIR);
doSignal.connect(m_signalStopAddr);
doSignal.send(&dummy, sizeof(dummy));
}
void * Requester::recieve_thread(void *arg)
{
zmq::socket_t * soc = (zmq::socket_t *) arg;
zmq::pollitem_t items[] =
{
{ *soc, 0, ZMQ_POLLIN, 0 },
{ *m_signalStop, 0, ZMQ_POLLIN, 0 }
};
while (1)
{
zmq::poll(items, 2, REQUEST_TIMEOUT_MS);
if (items[1].revents & ZMQ_POLLIN)
{
break; // exit
}
if (items[0].revents & ZMQ_POLLIN)
{
// process the event
}
}
// Cleanup
}
zmq::context_t* m_context;
zmq::socket_t* m_signalStop; // Don't forget to delete this!
char m_signalStopAddr[100];