这是我的密码

#include <pthread.h>
#include <stdio.h>

void cleanup(void *arg) {
    printf("cleanup: %s\n", (const char*)arg);
}

void *thr_fn1(void *arg) {
    printf("thread 1 strat\n");
    pthread_cleanup_push(cleanup, (void*)"thread 1 first handler");
    pthread_cleanup_push(cleanup, (void*)"thread 1 first handler");

    if(arg)
        return (void*)1;

    pthread_cleanup_pop(0);
    pthread_cleanup_pop(0);

    return (void*)1;
}

void *thr_fn2(void *arg) {
    printf("thread 2 strat\n");
    pthread_cleanup_push(cleanup, (void*)"thread 2 first handler");
    pthread_cleanup_push(cleanup, (void*)"thread 2 first handler");

    if(arg)
        return (void*)2;

    pthread_cleanup_pop(0);
    pthread_cleanup_pop(0);

    return (void*)2;
}

int main() {
    int err;
    pthread_t tid1, tid2;
    void *tret;

    pthread_create(&tid1, NULL, thr_fn1, (void*)1);
    pthread_create(&tid2, NULL, thr_fn2, (void*)1);

    pthread_join(tid1, &tret);
    printf("pthread 1 exit code %ld\n", tret);
    pthread_join(tid2, &tret);
    printf("pthread 2 exit code %ld\n", tret);

    return 0;
}

现在我使用gcc和g++运行它

$ gcc main.c -o main
$ ./main
thread 2 strat
thread 1 strat
pthread 1 exit code 1
pthread 2 exit code 2
$ g++ main.c -o main
$ ./main
thread 1 strat
cleanup: thread 1 first handler
cleanup: thread 1 first handler
thread 2 strat
cleanup: thread 2 first handler
cleanup: thread 2 first handler
pthread 1 exit code 1
pthread 2 exit code 2
$

1.为什么他们的行为不同？
1.其他函数的行为是否与此类似？
1.我发现gcc和g++的实现是不同的。那么哪一个是更好的实现呢？