c - 如何处理 pthread_kill 正常退出程序

Question

当我睡眠 1 秒时，我得到了通常的退出，但是当我注释掉sleep(1)并编译并运行程序时，我得到了killed为什么？我知道给睡眠不是正确的方法，我想知道如何处理我们必须调用 pthread kill 并确保线程正常退出的情况 |in a nutshell i want that atleast thread is created and running when pthread_kill is called

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
void *mythread(void *vargp)
{

        printf("Printing from Thread \n");
//      ...
        ...
        printf("End of thread\n");
}


int main()

{
        pthread_t thread_id;
        printf("main start\n");
        pthread_create(&thread_id, NULL, mythread, NULL);
        sleep(1); // <----------- Here
        pthread_kill(thread_id,SIGVTALRM);
}