How can I wait for any/all pthreads to complete?

Question

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

The threads come and go a lot for different reasons, and I really don\'

Answer 1

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:

• 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);
  }
}