用的软件是vscode

#include "apue.h"

void *thread_fun(void *arg){
    sleep(1);
    printf("wo shi new thread\n");
    return (void *)0;
}

int main(int argc, char **argv){
    pthread_t tid;
    int err;
    int s;
    void *rval;
    err = pthread_create(&tid, NULL, thread_fun, NULL);
    if (err) {  
        printf("pthread_create error\n");
        return 0;
    }
    //sleep(1);
    s = pthread_kill(tid,SIGQUIT);    //向新线程发送信号
    if (s == ESRCH){    //检测线程是否存在
        printf("new thread is not found\n");
    }
    printf("new thread exit code is %d\n",pthread_join(tid,&rval));
   /// system("pause");
    return 0;
}

#include "apue.h"中包含的头文件如下
#include<pthread.h>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<errno.h>
#include<unistd.h>
#include<sys/types.h>
#include <signal.h>

signal.h头文件中
#ifdef _POSIX
以下的显示为灰色
#define    SIGHUP    1    /* hangup */
#define    SIGQUIT    3    /* quit */
#define    SIGTRAP    5    /* trace trap (not reset when caught) */
#define SIGIOT  6       /* IOT instruction */
#define    SIGEMT    7    /* EMT instruction */
#define    SIGKILL    9    /* kill (cannot be caught or ignored) */
#define    SIGBUS    10    /* bus error */
#define    SIGSYS    12    /* bad argument to system call */
#define    SIGPIPE    13    /* write on a pipe with no one to read it */

#ifdef _POSIX 不是写得很清楚嘛