unix 線程回調函數使用-pthread_cleanup_push && pthread_cleanup_pop

#if 0 
線程結束時清理函數 
pthread_cleanup_push()，應該在線程開始的時候盡快執行初始化 
pthread_cleanup_pop()，當遇到以下三種各件會自動調用該函數，不需要PC執行到此函數 
1.調用pthread_exit() 
2.響應取消請求例如pthread_cancel() 
3.當pthread_cleanup_pop(arg)參數arg為非0時會線程退出時自動執行 
 
如果沒有以上三種情況，則不會執行； 
#endif 
 
#include <pthread.h> 
#include <stdio.h> 
#include <stdlib.h> 
#include <unistd.h> 
#include <semaphore.h> 
 
sem_t sm0,sm1,sm2,sm3; //信號量定義 信號量為控制線程的執行 
 
void ret_fn(void*str)//線程退出調用的回調函數 
{ 
    fputs(str,stdout); 
} 
 
 
void thread0(void) 
{ 
    if(0 != sem_wait(&sm0))//信號量進行阻塞 
    { 
        perror("sem_wait_0"); 
    } 
     
    char *str = "thead0_return_FN is runing\n"; 
    pthread_cleanup_push(ret_fn,str);//將回調函數入棧 
    fputs("thread0 is runing\n",stdout); 
    pthread_cleanup_pop(0);//將回調函數出棧，當遇到特定的條件會自動調用，不需要PC指到此才執行 
    return; 
} 
void thread1(void) 
{ 
    if(0 != sem_wait(&sm1)) 
    { 
        perror("sem_wait_1"); 
    } 
    char *str = "thead1_return_FN is runing\n"; 
    pthread_cleanup_push(ret_fn,str); 
    fputs("thread1 is runing\n",stdout); 
    pthread_exit((void*)1); 
    pthread_cleanup_pop(0); 
} 
 
void thread2(void) 
{ 
    if(0 != sem_wait(&sm2)) 
    { 
        perror("sem_wait_2"); 
    } 
    char *str = "thead2_return_FN is runing\n"; 
    pthread_cleanup_push(ret_fn,str); 
    fputs("thread2 is runing\n",stdout); 
    pthread_cleanup_pop(1); 
    fputs("線程結束才會執行pthread_cleanup_pop\n",stdout);//線程結束才會執行pthread_cleanup_pop 
} 
void thread3(void) 
{ 
    char *str = "thead3_return_FN is runing\n"; 
    pthread_cleanup_push(ret_fn,str); 
    if(0 != sem_wait(&sm3)) 
    { 
        perror("sem_wait_3"); 
    } 
    fputs("thread3 is runing\n",stdout); 
    usleep(100);// 讓主線程中的pthread_cancel可以執行 
    pthread_cleanup_pop(0); 
 
} 
 
int main(void) 
{ 
 
    pthread_t thd0,thd1,thd2,thd3; 
     
    if(0 != sem_init(&sm0,0,0))//初始化信號量 
    { 
        perror("sem_init_0"); 
        exit(1); 
    } 
    if(0 != sem_init(&sm1,0,0)) 
    { 
        perror("sem_init_0"); 
        exit(1); 
    } 
    if(0 != sem_init(&sm2,0,0)) 
    { 
        perror("sem_init_0"); 
        exit(1); 
    } 
    if(0 != sem_init(&sm3,0,0)) 
    { 
        perror("sem_init_0"); 
        exit(1); 
    } 
     
    if(0 != pthread_create(&thd0,NULL,(void*)thread0,NULL))//創建線程 
    { 
        perror("pthread_create_0\n"); 
        exit(1); 
    } 
    if(0 != pthread_create(&thd1,NULL,(void*)thread1,NULL)) 
    { 
        perror("pthread_create_1\n"); 
        exit(1); 
    } 
    if(0 != pthread_create(&thd2,NULL,(void*)thread2,NULL)) 
    { 
        perror("pthread_create_2\n"); 
        exit(1); 
    } 
    if(0 != pthread_create(&thd3,NULL,(void*)thread3,NULL)) 
    { 
        perror("pthread_create_3\n"); 
        exit(1); 
    } 
    unsigned char status = 0xF;//控制重復測試掩碼 
     
    while(1) 
    { 
        fputs("請輸入測試選項：0(沒有調用回調函數),１(pthread_exit),2(pthread_cancel),3(參數非0 pthread_cleanup_pop)\n",stdout); 
        int in; 
        scanf("%d",&in); 
        switch(in) 
        { 
            case 0: 
                { 
                    if(!(status & 0x1)) 
                    { 
                        fputs("這個項目已測試過，請選擇其它，謝謝\n",stdout); 
                        break; 
                    } 
                    if(0 != sem_post(&sm0))//激活信號量，讓子線程THD0繼續執行 
                    { 
                        perror("sem_post_0\n"); 
                    } 
                    status &= 0xe; 
                    break; 
                } 
            case 1: 
                { 
                    if(!(status & 0x2)) 
                    { 
                        fputs("這個項目已測試過，請選擇其它，謝謝\n",stdout); 
                        break; 
                    } 
                    if(0 != sem_post(&sm1)) 
                    { 
                        perror("sem_post_1\n"); 
                    } 
                    status &= 0xc; 
                    break; 
                }        
            case 2: 
                { 
                    if(!(status & 0x4)) 
                    { 
                        fputs("這個項目已測試過，請選擇其它，謝謝\n",stdout); 
                        break; 
                    } 
                    if(0 != sem_post(&sm2)) 
                    { 
                        perror("sem_post_2\n"); 
                    } 
                    status &= 0xb; 
                    break; 
                } 
            case 3: 
                { 
                    if(!(status & 0x8)) 
                    { 
                        fputs("這個項目已測試過，請選擇其它，謝謝\n",stdout); 
                        break; 
                    } 
                    if(0 != sem_post(&sm3)) 
                    { 
                        perror("sem_post_3\n"); 
                    } 
                    pthread_cancel(thd3); 
                    status &= 0x7; 
                    break; 
                } 
            default: break; 
        }    
        sleep(1); 
    } 
 
     
    return 0; 
}