#include<stdio.h>
#include<stdlib.h>
#include<pthread.h>

pthread_once_t once = PTHREAD_ONCE_INIT;          //指定參数位仅仅运行一次

void run(void)                                        //演示样例线程函数
{
	printf("function run is runing in thread %d\n",pthread_self());
}

void *thread1(void *arg)
{
	pthread_t thid = pthread_self();                   //接受而且打印当前线程的ID
	printf("current thread id is %d\n",thid);           //调用运行线程函数仅仅运行一次，接受一个标志參数和一个目标函数的指针
	pthread_once(&once,run);
	printf("thread1 ends\n");                           //打印函数调用结束提示信息
}

void *thread2(void *arg)
{
	pthread_t thid = pthread_self();                  //接受而且打印当前线程ID
	printf("current thread is ID %u\n",thid);
	pthread_once(&once,run);                         //调用函数同上以一个函数结构。可是这里并不会成功调用由于仅仅运行一次
	printf("thread2 ends\n");                         //打印函数调用结束信息
}
int main()
{
	pthread_t thid1,thid2;                             //定义两个线程ID
	pthread_create(&thid1,NULL,thread1,NULL);           //创建线程。调用上边的函数1和函数2
	pthread_create(&thid2,NULL,thread2,NULL);
	sleep(3);                                          //主线程（进程）暂停3秒后继续运行
	printf("main thread exit!\n");
	exit(0);
}

typedef struct

{

       int                              detachstate;   线程的分离状态

       int                              schedpolicy;  线程调度策略

       struct sched_param           schedparam;  线程的调度參数

       int                              inheritsched;  线程的继承性

       int                               scope;       线程的作用域

       size_t                          guardsize;   线程栈末尾的警戒缓冲区大小

       int                               stackaddr_set;

       void *                         stackaddr;   线程栈的位置

       size_t                          stacksize;    线程栈的大小

}pthread_attr_t;

#include<stdio.h>
#include<pthread.h>
#include<stdlib.h>

void assisthread(void *arg)                   //演示样例线程函数
{
	printf("i am nothing helping to do some thing\n");
	sleep(3);                                //暂停三秒
	//pthread_exit(0);     
	//线程结束
	exit(0);
}

int main()
{
	pthread_t   assisthid;
	int         status   ;

	pthread_create(&assisthid,NULL,(void *)assisthread,NULL);     //创建线程
	pthread_join(assisthid,(void *)&status);                      //等待指定线程结束
	printf("assistthread‘s exit is caused %d\n",status);

	return 0;

#include<stdio.h>
#include<stdlib.h>
#include<pthread.h>

pthread_key_t key;          //定义全局变量，键

void *thread2(void *arg)        //第二个函数
{
	int tsd = 5;                   //自己线程的私有数据
	printf("thread %d is runing \n",pthread_self());
	pthread_setspecific(key,(void *)tsd);       //设置一个私有数据
	printf("thread %d return %d\n",pthread_self(),pthread_getspecific(key));
}

void *thread1(void *arg)//创建线程一然后调用函数二创建还有一个线程
{
	int tsd = 0;
	pthread_t thid2;

	printf("thread %d is runing\n",pthread_self());
	pthread_setspecific(key,(void *)tsd);
	pthread_create(&thid2,NULL,thread2,NULL);
	sleep(5);
	printf("thread %d return %d\n",pthread_self(),pthread_getspecific(key));
}

int main()
{
	pthread_t thid1;
	printf("main thread begins running\n");
	pthread_key_create(&key,NULL);              //创建一个键
	pthread_create(&thid1,NULL,thread1,NULL);   //调用函数一创建线程1
	sleep(3);
	pthread_key_delete(key);                    //删除键
	printf("main thread exit\n");
	return 0;
}