#include <stdio.h>

#include <unistd.h>

#include <signal.h>

#include <string.h>

#include <sys/time.h>

#include <errno.h>



void PrintMsg(int Num)

{

    printf("%s\n", "Hello World");



    return;

}



int main(int argc, char* argv[])

{

    signal(SIGALRM, PrintMsg);



    struct itimerval tick;

    tick.it_value.tv_sec = 10;  //十秒鐘后將啟動定時器

    tick.it_value.tv_usec = 0;

    tick.it_interval.tv_sec  =1; //定時器啟動后，每隔1秒將執行相應的函數

    tick.it_interval.tv_usec = 0;



    //setitimer將觸發SIGALRM信號

    int ret = setitimer(ITIMER_REAL, &tick, NULL);



    if ( ret != 0)

    {

        printf("Set timer error. %s \n", strerror(errno) );



        return -1;

    }



    printf("Wait!\n");



    getchar();



    return 0;

}