/* pthread.c by detour@metalshell.com
 *
 * Create multiple POSIX thread processes and wait for
 * each one to complete.
 *
 * http://www.metalshell.com/
 *
 */
 
#include <unistd.h>
#include <pthread.h>
#include <stdio.h>
#include <time.h>
 
#define NUM_THREADS 10
 
/* This becomes the main() of the new thread.  It
   is requred to return void * and take void * as a
   parameter. */
void *thread_function(void *arg) {
  fprintf(stdout, "Thread: %d running.\n", (int)arg);
 
  // Sleep for arg+1 seconds to verify pthread_join.
  sleep((int)arg+1);
 
  fprintf(stdout, "Thread: %d done.\n", (int)arg);
 
  pthread_exit(0);
}
 
int main() {
  int cnt;
  pthread_t p_thread[NUM_THREADS];
 
  for(cnt = 0; cnt < NUM_THREADS; cnt++)
    /* Returns 0 on successful creation of the thread.  The second
       parameter, left NULL for this example,  allows for options
       like CPU scheduling to be set. */
    if(pthread_create(&p_thread[cnt], NULL, thread_function, (void *)cnt) != 0)
      fprintf(stderr, "Error creating the thread");
 
  // Cycle through each thread and wait until it is completed.
  for(cnt = 0; cnt < NUM_THREADS; cnt++) {
    // Waits for p_thread[cnt] to finish.
    pthread_join(p_thread[cnt], NULL);
  }
 
  fprintf(stdout, "All threads completed.\n");
 
  return 0;
}