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我最近开始使用信号进行编程。我用他们在C.我的多线程服务器的代码下面是代码相关的信号的一部分,但它不工作,因为它应该做的:为什么此代码无法按预期工作?
信号处理程序:
void* Ctrl_C_handler(void *arg)
{
int *sock_fd_ptr = (int*)arg;
sigset_t set;
int err, sig;
err = sigemptyset(&set); // Clear the signals holder set
if(err) perror("sigemptyset(&set)");
err = sigaddset(&set, SIGINT); // Add the SIGINT: Ctrl+C
if(err) perror("siaddset(&set, SIGINT)");
err = pthread_sigmask(SIG_UNBLOCK, &set, NULL); // Set mask as to unblock SIGINT
if(err) perror("pthread_sigmask(SIG_SETMASK, &set, NULL)");
printf("Signal handler active:\n");
while(1) // Ctrl+C
{
err = sigwait(&set, &sig); // Wait for signal to occur
if(err)
{
perror("sigwait(&set, &sig)");
printf("Error handling the signal, SigHandlerThread exiting..\n");
break;
}
if(sig == SIGINT)
{
printf("Ctrl+C detected by server !!\n");
printf("No more connections will be accepted!!");
if(*sock_fd_ptr > 0)
{
close(*sock_fd_ptr);
*sock_fd_ptr = -1;
break;
}
}
}
return NULL;
}
在main():
/*********** Signal Handling *************/
sigset_t set; // declare a set to hold the signals
err = sigfillset(&set); // Fill the set with all the signals
if(err) perror("sigfillset(&set)");
err = sigthreadmask(SIG_BLOCK, &set, NULL); // Block/Mask the signals in the set
if(err) perror("sigthreadmask(SIG_BLOCK, &set, NULL)");
err = pthread_create(&sig_handler_tid, NULL, Ctrl_C_handler, (void *)&sock_fd);
// Create a thread for handling signals
if(err) perror("pthread_create");
我读这个方法here。我尝试从不同的终端窗口发送kill -s SIGINT <pid of my program>
,但程序退出。
你在信号处理程序中做得太多了。请记住,你的程序中断了!那么你真的想要(1)吗?也不是printf,也不perror是异步信号安全的。 – zoska