#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <pthread.h>

static void *tick_thread(void *unused)
{
    while (1) {
        pthread_testcancel();
        printf("tick\n");
        sleep(1);
    }
    return NULL;
}

int main(int argc, char **argv)
{
    pid_t pid;
    pthread_t tid;
    void *ret;

    if (pthread_create(&tid, NULL, tick_thread, NULL) < 0) {
        printf("pthread_create failed\n");
        return 1;
    }

    pid = vfork();
    if (pid == 0) {
        printf("sleeping\n");
        sleep(10);
        printf("done sleeping\n");
        execl("/bin/echo", "echo", "hello world", NULL);
        exit(1);
    } else if (pid > 0) {
        printf("vfork() returned\n");
        waitpid(pid, NULL, 0);
    } else {
        printf("vfork failed\n");
        return 1;
    }

    pthread_cancel(tid);
    pthread_join(tid, &ret);

    return 0;
}