thread_16

#include <stdlib.h>
#include <pthread.h>
#include <stdio.h>
#include <sched.h>
#include <sched.h>
void *consumer1(void *p)
{
        do{
          printf("<<<(%u),%d\n", (unsigned)pthread_self(),1);
        }while(1);
}
 void *consumer2(void *p)
 {
         do{
             printf("<<<(%u),%d\n", (unsigned)pthread_self(), 2);
             struct sched_param sched;
             sched.__sched_priority = 99;
        //pthread_setschedparam(*(pthread_t *)p, SCHED_FIFO, &sched);
        }while(1);
 }
int main(int argc, char *argv[])
{
        pthread_t  t1, t2, t3;
         int ret;
        struct sched_param param;
         param.sched_priority = 1;
        pthread_attr_t attr;
        pthread_attr_init(&attr);

         pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
         pthread_attr_setschedpolicy(&attr, SCHED_FIFO);
         pthread_attr_setschedparam(&attr, &param);

        ret = pthread_create(&t1, NULL, consumer1, NULL);
        sleep(2);
         ret = pthread_create(&t2, &attr, consumer2,(void *)&t1);//注意看最后一个参数
         if(ret != 0)
         {
                printf("create failed,%d\n", ret);
               exit(1);
         }
         pthread_attr_destroy(&attr);
         sleep(1);
         printf("main returned\n");
      return 0;
 }
/*运行结果：
1.最终一直运行  void *consumer1(void *p)，
2.如果把18行注释掉，最终一直运行void *consumer2(void *p)，
3.在18行第一个子线程的被改为实时并优先级大于第二个线程，所以它抢占cpu并一直运行。
4.如果第一个线程优先级设置小于第二个线程，还是一直运行void *consumer2(void *p)。
5.如果17, 18行改为
sched.__sched_priority = 0;
pthread_setschedparam(pthread_self(), SCHED_OTHER,     &sched);
第二个线程将会变为普通线程*/