void pthread_cleanup_push(void (*rtn)(void *), void *arg);注册一个线程终止时的清理函数 (类似atexit),后注册的先执行。
void pthread_cleanup_pop(int execute); 解除注册最近一个注册的线程清理函数,即线程清理函数使用类似栈的压 (push)、弹(pop)方式进行注册和解除;参数 execute 为0 时表示仅解除注册,而不执行,非 0 则表示执行该清理函数并解除注册;
要特别注意的是,pthread_cleanup_push (3)和pthread_cleanup_pop (3)可能是通过宏来实现的,必须 在同一个缩进级别的代码块中配对使用,即编写代码时不能只调用其中一个,否则编译将通不过。因为它们的宏实现通常使用了单的花括号。
(PS:这时,线程的结束方式应该为pthread_exit(),而不是return。
更不是exit(),_exit(),abort()这些是进程的结束方式,会导致整个进程结束)
#include "apue.h" // http://www.apuebook.com/ 网站上找这个头文件 #include <pthread.h> void cleanup(void *arg) { printf("cleanup: %s\n", (char *)arg); } void *thr_fn1(void *arg) { printf("thread 1 start\n"); pthread_cleanup_push(cleanup, "thread 1 first handler"); pthread_cleanup_push(cleanup, "thread 1 second handler"); printf("thread 1 push complete:%d\n",arg); if (arg) return((void *)1); pthread_cleanup_pop(0); pthread_cleanup_pop(0); return((void *)1); } void *thr_fn2(void *arg) { printf("thread 2 start\n"); pthread_cleanup_push(cleanup, "thread 2 first handler"); pthread_cleanup_push(cleanup, "thread 2 second handler"); printf("thread 2 push complete: %d\n",arg); if (arg) pthread_exit((void *)2); pthread_cleanup_pop(0); pthread_cleanup_pop(0); pthread_exit((void *)2); } int main(void) { int err; pthread_t tid1, tid2; void *tret; err = pthread_create(&tid1, NULL, thr_fn1, (void *)1); if (err != 0) err_quit("can't create thread 1: %s\n", strerror(err)); err = pthread_create(&tid2, NULL, thr_fn2, (void *)1); if (err != 0) err_quit("can't create thread 2: %s\n", strerror(err)); err = pthread_join(tid1, &tret); if (err != 0) err_quit("can't join with thread 1: %s\n", strerror(err)); printf("thread 1 exit code %d\n", (int)tret); err = pthread_join(tid2, &tret); if (err != 0) err_quit("can't join with thread 2: %s\n", strerror(err)); printf("thread 2 exit code %d\n", (int)tret); exit(0); }