[置顶] linux线程私有数据
今天在看线程的私有数据时，一直想找个例子，实际的验证下，用数据告诉自己:"对，就是那样的，那就是TSD“,于是乎我看到了这个例子
http://www.ibm.com/developerworks/cn/linux/thread/posix_threadapi/part2/，不得不说IBMdeveloperworkshop这的很好，有很多非常优秀的文章，至于原创与否我没有考证，不下结论，于是乎下面的代码，纷纷的被转载，转载，继续转载。我百度 ”线程私有数据“，前几篇都是来自对IBM的转载，我晕死了，那个例子个人真心感觉不是很好的体现了线程私有数据的特性，另外作者专门说明:以下这个例子没有什么实际意义，只是说明如何使用，以及能够使用这一机制达到存储线程私有数据的目的。
原作者代码：
#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;好吧，吐槽完毕，上自己的代码，证明下linux的线程私有数据
[fy@localhost 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;
}
使宏定义判断为假，可以作对比测试。
运行结果如下：
[fy@localhost 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 [fy@localhost pthread_key_create]$线程1把全局变量设置为自己的私有数据，创建线程2，线程2获得数据，数据依旧是10，也就是说线程1修改没有影响全局，线程2设置为自己的私有数据，继续修改之，回到线程1，取出私有数据，还是自己设置的数据，也就是线程2的修改没有影响线程1的私有数据，两个线程都退出，全局变量依旧是10.