我怎么能等待任何/所有的pthreads才能完成？ [英] How can I wait for any/all pthreads to complete?

问题描述

我只希望我的主线程等待任何和我所有的（P）线程退出之前完成。

I just want my main thread to wait for any and all my (p)threads to complete before exiting.

中的线程来来去去很多不同的原因，我真的不想让他们都跟踪 - 我只是想知道，当他们都走了。

The threads come and go a lot for different reasons, and I really don't want to keep track of all of them - I just want to know when they're all gone.

wait（）的这是否为子进程的时候，有没有孩子离开返回ECHILD，但等待不（出现一起工作）（P）的线程。

wait() does this for child processes, returning ECHILD when there are no children left, however wait does not (appear to work with) (p)threads.

我真的不想去通过保持每一个优秀的线程列表的麻烦（因为他们来来去去），则不必调用在pthread_join每个

I really don't want to go through the trouble of keeping a list of every single outstanding thread (as they come and go), then having to call pthread_join on each.

由于有一个快速和肮脏的方式做到这一点？

As there a quick-and-dirty way to do this?

推荐答案

的正确方法是跟踪所有pthread_id的的，但你问一个快速和肮脏的方式，以便在这儿呢。基本上是：

The proper way is to keep track of all of your pthread_id's, but you asked for a quick and dirty way so here it is. Basically:

• 只是保持运行的线程的总数，


• 之前调用pthread_create的，
在主循环加一

• 递减的线程数，因为每个线程结束。


• 然后睡在主过程结束，直到将返回到0。

• just keep a total count of running threads,
• increment it in the main loop before calling pthread_create,
• decrement the thread count as each thread finishes.
• Then sleep at the end of the main process until the count returns to 0.

volatile int running_threads = 0;
pthread_mutex_t running_mutex = PTHREAD_MUTEX_INITIALIZER;

void * threadStart()
{
   // do the thread work
   pthread_mutex_lock(&running_mutex);
   running_threads--;
   pthread_mutex_unlock(&running_mutex);
}

int main()
{
  for (i = 0; i < num_threads;i++)
  {
     pthread_mutex_lock(&running_mutex);
     running_threads++;
     pthread_mutex_unlock(&running_mutex);
     // launch thread

  }

  while (running_threads > 0)
  {
     sleep(1);
  }
}

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