linux运行多线程

/*                                                                  
 * POSIX Real Time Example
 * using a single pthread as RT thread
 */
/*gcc -o rt_example rt_example.c -lpthread -lrt -Wall
  sudo ./rt_example */
 
#include <limits.h>
#include <pthread.h>
#include <sched.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>

/*struct sched_param param;
pthread_attr_t attr;
pthread_t thread;

struct sched_param param1;
pthread_attr_t attr1;
pthread_t thread1;*/

struct sched_param param[2];
pthread_attr_t attr[2];
pthread_t thread[2];

void *thread_func(void *data)
{
   /* Do RT specific stuff here */
   printf("thread1: hello preempt_rt\n\r");
   while(1)
       pthread_testcancel();
   return NULL;
}

void *thread_func1(void *data)
{
   /* Do RT specific stuff here */
   printf("thread2: hello preempt_rt\n\r");
   while(1)
        pthread_testcancel();
   return NULL;
}
 
int rt_thread(void)
{
   int ret;
 
   param[0].sched_priority = 80;
   ret = pthread_attr_setschedparam(&attr[0], &param[0]);
   if (ret) {
      printf("pthread setschedparam failed\n");
      goto out;
   }
  
   /* Create a pthread with specified attributes */
   ret = pthread_create(&thread[0], &attr[0], thread_func, NULL);
   if (ret) {
      printf("create pthread failed\n");
      goto out;
   }
   
out:
   return ret;
}

int rt_thread1(void)
{
   int ret;

   param[1].sched_priority = 80;
   ret = pthread_attr_setschedparam(&attr[1], &param[1]);
   if (ret) {
      printf("pthread setschedparam failed\n");
      goto out;
   }
 
   /* Create a pthread with specified attributes */
   ret = pthread_create(&thread[1], &attr[1], thread_func1, NULL);
   if (ret) {
      printf("create pthread failed\n");
      goto out;
   }
 
out:
   return ret;
}

int main(int argc, char* argv[])
{
   int ret=0;
   void* retval;
   int i;

   /* Lock memory */
   if(mlockall(MCL_CURRENT|MCL_FUTURE) == -1) {
      printf("mlockall failed: %m\n");
      exit(-2);
   }
 
   for(i=0;i<2;i++) {
      /* Initialize pthread attributes (default values) */
      ret = pthread_attr_init(&attr[i]);
      if (ret) {
         printf("init pthread attributes failed\n");
         goto out;
      }
 
      /* Set a specific stack size  */
      ret = pthread_attr_setstacksize(&attr[i], PTHREAD_STACK_MIN);
      if (ret) {
         printf("pthread setstacksize failed\n");
         goto out;
      }
 
      /* Set scheduler policy and priority of pthread */
      ret = pthread_attr_setschedpolicy(&attr[i], SCHED_FIFO);
      if (ret) {
         printf("pthread setschedpolicy failed\n");
         goto out;
      }
   
      /* Use scheduling parameters of attr */
      ret = pthread_attr_setinheritsched(&attr[i], PTHREAD_EXPLICIT_SCHED);
      if (ret) {
         printf("pthread setinheritsched failed\n");
         goto out;
      }
   }

   rt_thread();
   rt_thread1();

   pthread_cancel(thread[0]);
   pthread_cancel(thread[1]);

   /* Join the thread and wait until it is done */
   ret = pthread_join(thread[0],&retval);
   if (ret)
       printf("join pthread failed: %m\n");

   printf("thread retval is %d\n",(int*)retval);

   ret = pthread_join(thread[1],&retval);
   if (ret)
       printf("join pthread failed: %m\n");

   printf("thread retval is %d\n",(int*)retval);
  
out: 
   return ret;     
}