void pthread_cleanup_push(void (*rtn)(void *), void *arg);     // 註冊清理函式
void pthread_cleanup_pop(int execute);     // 根據引數決定是否呼叫清理函式

• 執行緒呼叫pthread_exit時。
• 響應其它執行緒發來的pthread_cancel取消請求時。
• pthread_cleanup_pop的引數不為0時。

#include <stdio.h>
#include <pthread.h>
 
// 執行緒清理處理程式
void cleanup(void *arg)
{
    printf("cleanup : %s\n", (char *)arg);
}
 
void *thr_fn1(void *arg)
{
    pthread_cleanup_push(cleanup, "This is thread 1\n");
    return ((void *)1);       // 返回不會呼叫清理函式
    pthread_cleanup_pop(0); // 配對作用
}
 
void *thr_fn2(void *arg)
{
    pthread_cleanup_push(cleanup, "This is thread 2\n");
    pthread_exit((void *)2);   // exit時會呼叫清理函式
    pthread_cleanup_pop(0);     // 配對作用
}
 
void *thr_fn3(void *arg)
{
    pthread_cleanup_push(cleanup, "This is thread 3\n");
    sleep(3);               // 等待控制執行緒發出取消請求，然後呼叫清理函式
    pthread_cleanup_pop(0); // 配對作用
}
 
void *thr_fn4(void *arg)
{
    pthread_cleanup_push(cleanup, "This is thread 4\n");
    pthread_cleanup_pop(1); // 引數為0，則清理函式不被呼叫
}
 
int main(void)
{
    pthread_t tid1, tid2, tid3, tid4;
 
    pthread_create(&tid1, NULL, thr_fn1, NULL);
    pthread_create(&tid2, NULL, thr_fn2, NULL);
    pthread_create(&tid3, NULL, thr_fn3, NULL);
    pthread_create(&tid4, NULL, thr_fn4, NULL);
 
    pthread_cancel(tid3);
 
    sleep(3);
 
    return 0;
}