今天在看執行緒的私有資料時，一直想找個例子，實際的驗證下，用資料告訴自己:"對，就是那樣的，那就是TSD“,於是乎我看到了這個例子

http://www.ibm.com/developerworks/cn/linux/thread/posix_threadapi/part2/，不得不說IBMdeveloperworkshop這的很好，有很多非常優秀的文章，至於原創與否我沒有考證，不下結論，於是乎下面的程式碼，紛紛的被轉載，轉載，繼續轉載。我百度 ”執行緒私有資料“，前幾篇都是來自對IBM的轉載，我暈死了，那個例子個人真心感覺不是很好的體現了執行緒私有資料的特性，另外作者專門說明:以下這個例子沒有什麼實際意義，只是說明如何使用，以及能夠使用這一機制達到儲存

原作者程式碼：

#include <stdio.h>
#include <pthread.h>
pthread_key_t   key;
void echomsg(int t)
{
        printf("destructor excuted in thread %d,param=%d\n",pthread_self(),t);
}
void * child1(void *arg)
{
        int tid=pthread_self();
        printf("thread %d enter\n",tid);
        pthread_setspecific(key,(void *)tid);
        sleep(2);
        printf("thread %d returns %d\n",tid,pthread_getspecific(key));
        sleep(5);
}
void * child2(void *arg)
{
        int tid=pthread_self();
        printf("thread %d enter\n",tid);
        pthread_setspecific(key,(void *)tid);
        sleep(1);
        printf("thread %d returns %d\n",tid,pthread_getspecific(key));
        sleep(5);
}
int main(void)
{
        int tid1,tid2;
        printf("hello\n");
        pthread_key_create(&key,echomsg);
        pthread_create(&tid1,NULL,child1,NULL);
        pthread_create(&tid2,NULL,child2,NULL);
        sleep(10);
        pthread_key_delete(key);
        printf("main thread exit\n");
        return 0;
 

[[email protected] pthread_key_create]$ less main.c 
#include <stdio.h>
#include <string.h>
#include <pthread.h>
#include <unistd.h>
#define KEY
pthread_key_t key;
int tsd=10;
void * thread2(void *arg)
{
        printf("before enter thread 2 the global's tsd is %d\n",tsd);
        #ifdef KEY
                pthread_setspecific(key,(void *)tsd);
                key=5;
                printf("after thread2 modify the thread2's own tsd is ----- %d\n",pthread_getspecific(key));
        #endif
        printf("after modify the global's tsd is %d \n",tsd);
        pthread_exit((void*)0);
        return NULL;
}
void * thread1(void *arg)
{
        printf("before enter the thread 1 the global's tsd is %d\n",tsd);
        pthread_t thid2;
        #ifdef KEY
                pthread_setspecific(key,(void *)tsd);
                key=0;
                printf("after thread1 modify ----thread1's own tsd is  %d\n",pthread_getspecific(key));
        #endif
        pthread_create(&thid2,NULL,thread2,NULL);
        pthread_join(thid2,NULL);
        #ifdef KEY
                printf("after thread2  modify   thread1's own tsd  is ----- %d\n",pthread_getspecific(key));
        #endif
        printf("after the thread2 the global's tsd is %d\n",tsd);
        pthread_exit((void*)0);
}
void test1()
{
        pthread_t thid1;
        printf("main thread begins running\n");
        #ifdef KEY
                pthread_key_create(&key,NULL);
        #endif
        pthread_create(&thid1,NULL,thread1,NULL);
        pthread_join(thid1,NULL);
        sleep(3);
        #ifdef KEY
                pthread_key_delete(key);
        #endif
        printf("main thread exit\n");
}
int main(int argc, char **argv)
{
        test1();
        return 0;
}
 

[[email protected] pthread_key_create]$ ./run 
main thread begins running
before enter the thread 1 the global's tsd is 10
after thread1 modify ----thread1's own tsd is  10
before enter thread 2 the global's tsd is 10
after thread2 modify the thread2's own tsd is ----- 0
after modify the global's tsd is 10 
after thread2  modify   thread1's own tsd  is ----- 0
after the thread2 the global's tsd is 10
main thread exit
[[email protected] pthread_key_create]$