POSIX线程库

#include<pthread.h>
#include<stdio.h>
int sum;
/* this sum data is shared by the thread(s) */
/* threads call this function */
void *runner(void *param);
int main(int argc, char *argv[]){
   pthread t tid; /* the thread identifier */
   /* set of thread attributes */
   pthread attr t attr;
   if (argc != 2){
      fprintf(stderr,"usage: a.out </p><p>");
      return -1;
   }
   if (atoi(argv[1]) < 0){
      fprintf(stderr,"%d must be >= 0</p><p>",atoi(argv[1]));
      return -1;
   }
   /* get the default attributes */
   pthread attr init(&attr); /* create the thread */
   pthread create(&tid,&attr,runner,argv[1]);
   /* wait for the thread to exit */
   pthread join(tid,NULL);
   printf("sum = %d</p><p>",sum);
}
/* The thread will now begin control in this function */
void *runner(void *param){
   int i, upper = atoi(param);
   sum = 0;
   for (i = 1; i <= upper; i++)
      sum += i;
   pthread exit(0);
}