#include 
     
      #include 
      
       void *start_routine(void *arg){        while(1)        {                system("service httpd restart");                system("service mysqld restart");                sleep(60*60*6);        }        int retvalue = 0;        pthread_exit((void*)&retvalue);}int main(){        pthread_t pt;        int ret;        ret = pthread_create(&pt,NULL,(void*)start_routine,0);        if(ret != 0)        {                printf("create thread error");                return 0;        }        int *ret_join = NULL;        pthread_join(pt,(void*)&ret_join);        printf("retvalue: %d\n",*ret_join);        return 0;}
      
     

 gcc test.c -o test -lpthread