/*lsp signal()함수 예제2 304p~305p*/
/*ssu_signal_2.c*/
/*20162468 박다은*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <sys/time.h> //gettimeofday

static void ssu_signal_handler(int signo);

int main()
{
    struct timeval A, B, C; //시간을 비교할 값들
    gettimeofday(&A, NULL);
    //=======================================

    if(signal(SIGINT, ssu_signal_handler) == SIG_ERR){ //handler
        fprintf(stderr, "cannot handle SIGINT\n");
        exit(EXIT_FAILURE);
    }
    if(signal(SIGTERM, ssu_signal_handler) == SIG_ERR){ //handler
        fprintf(stderr, "cannot handle SIGTERM\n");
        exit(EXIT_FAILURE);
    }
    if(signal(SIGPROF, SIG_DFL) == SIG_ERR){ //default
        fprintf(stderr, "cannot reset SIGPROF\n");
        exit(EXIT_FAILURE);
    }
    if(signal(SIGHUP, SIG_IGN) == SIG_ERR){ //ignore
        fprintf(stderr, "cannot ignore SIGHUP\n");
        exit(EXIT_FAILURE);
    }

    while(1)
        pause();

    //=======================================
    gettimeofday(&B, NULL);

    C.tv_sec = B.tv_sec - A.tv_sec;
    C.tv_usec = B.tv_usec - A.tv_usec;
    if(C.tv_usec < 0){
        C.tv_sec -= 1;
        C.tv_usec += 1000000;
    }
    printf("ROLLCAKE::Running Time : %ld µs\n", C.tv_sec*1000000 + C.tv_usec); //작은 프로그램이므로 마이크로초로 계산
    exit(0);
}

void ssu_signal_handler(int signo){
    if(signo == SIGINT)
        printf("caught SIGINT\n");
    else if(signo == SIGTERM)
        printf("caught SIGTERM\n");
    else{
        fprintf(stderr, "unexpected signal\n");
        exit(EXIT_FAILURE);
    }

    exit(EXIT_SUCCESS);
}