我有一个项目,我正在将作业添加到队列中,并且我有多个线程正在进行作业,并计算出自己的独立结果。如何停止在pthread_join上停滞的线程?
我的程序处理SIGINT信号,我试图加入线程来合并结果,打印到屏幕,然后退出。我的问题是,当我发送信号时线程似乎停止工作,或者他们在mutex_lock上被阻塞。这里是我的程序的重要部分,以便简洁。
的main.c
//the thread pool has a queue of jobs inside
//called jobs (which is a struct)
struct thread_pool * pool;
void signal_handler(int signo) {
pool->jobs->running = 0; //stop the thread pool
pthread_cond_broadcast(pool->jobs->cond);
for (i = 0; i < tpool->thread_count; i++) {
pthread_join(tpool->threads[i], retval);
//do stuff with retval
}
//print results then exit
exit(EXIT_SUCCESS);
}
int main() {
signal(SIGINT, signal_handler);
//set up threadpool and jobpool
//start threads (they all run the workerThread function)
while (1) {
//send jobs to the job pool
}
return 0;
}
thread_stuff.c
void add_job(struct jobs * j) {
if (j->running) {
pthread_mutex_lock(j->mutex);
//add job to queue and update count and empty
pthread_cond_signal(j->cond);
pthread_mutex_unlock(j->mutex);
}
}
struct job * get_job(struct jobs * j) {
pthread_mutex_lock(j->mutex);
while (j->running && j->empty)
pthread_cond_wait(j->cond, j->mutex);
if (!j->running || j->empty) return NULL;
//get the next job from the queue
//unlock mutex and send a signal to other threads
//waiting on the condition
pthread_cond_signal(j->cond);
pthread_mutex_unlock(j->mutex);
//return new job
}
void * workerThread(void * arg) {
struct jobs * j = (struct jobs *) arg;
int results = 0;
while (j->running) {
//get next job and process results
}
return results;
}
感谢您的帮助,这是给我一个真正的头痛!
如果您阅读[此POSIX信号概念参考](http://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_04),您将在2.4.3节的末尾看到一个列表的* async-safe *函数,因此可以从信号处理程序安全地使用。如果您查看该列表,您会看到['pthread_join](http://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_join.html)*未列出。这意味着你不应该在信号处理程序中调用它。 –