代码：

#include<stdio.h>
#include<pthread.h>
static int run=-1;
static int retvalue;
void *start_routine(void *arg)
{
	int *running =arg;
	printf("child Thread initial over,pass in parameters:%d\n",*running);
	while(*running)
	{
		printf("child thread is running\n");
		usleep(1);
	}
	printf("child thread quit\n");
	retvalue=8;
	pthread_exit((void*)&retvalue);
}
int main(void)
{
	pthread_t pt;
	int ret=-1;
	int times=3;
	int i=0;
	int *ret_join=NULL;
	ret=pthread_create(&pt,NULL,(void*)start_routine,&run);
	if(ret!=0)
	{
		printf("create thread failed!\n");
		return 1;		
	}
	usleep(1);
	for(;i<times;i++)
	{
		printf("main thread print\n");
		usleep(1);
	}		
	run=0;
	pthread_join(pt,(void*)&ret_join);
	printf("thread back value is:%d\n",*ret_join);
	return 0;
}

运行

第一次：

第二次

前后两次结果不一致，主要是两个线程争夺CPU资源造成的