pthread_hw.c

简单的多线程程序

#include <stdio.h>
#include <pthread.h>
#include <sched.h>
pthread_mutex_t mutex;
struct timespec delay;
void
ptr_key (void)
{
  pthread_key_t mykeyt;
  int par = 5;
  printf ("the value got from key is:%d\n", par);
}

void
thread_obj (int prior)
{
  int j = 2, i, k = 2;
  pthread_key_t mykey;
  pthread_key_create (&mykey, NULL);
  pthread_setspecific (mykey, &j);
  j = prior + 4;
  printf ("The pthread process number is:%d\n", k);
  ptr_key ();
  usleep (20000);
  for (i = 0; i < 10; i++)
    {
      if (i % 2 == 1)
	{
	  pthread_mutex_lock (&mutex);
	  printf ("%d:%d\n", k, i);
	  pthread_mutex_unlock (&mutex);
	  usleep (50000);
	  // pthread_delay_np(&delay);
	}
    }
  // printf("the pthread priority is:%d\n",prior);
}

int
main (void)
{
  pthread_t id;
  pthread_attr_t attr;
  struct sched_param param;
  int i = 0, ret, k = 1;
  delay.tv_sec = 2;
  delay.tv_nsec = 0;
  pthread_attr_init (&attr);
  pthread_attr_getschedparam (&attr, &param);
  pthread_attr_setscope (&attr, PTHREAD_SCOPE_SYSTEM);
  printf ("The main process number is:%d\n", k);
  ret =
    pthread_create (&id, &attr, (void *) thread_obj,
		    (int) param.sched_priority);
  if (ret != 0)
    printf ("create pthread error\n");
  for (i = 0; i < 10; i++)
    {
      if (i % 2 == 0)
	{
	  pthread_mutex_lock (&mutex);
	  printf ("%d:%d\n", k, i);
	  pthread_mutex_unlock (&mutex);
	  usleep (50000);
	  //pthread_delay_np(&delay);
	}
    }
  pthread_join (id, NULL);
  printf ("this is end  program\n");
  return (0);
}