System_Software_HandsOnList2/001b.c at main · superv13/System_Software_HandsOnList2 · GitHub

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/*
..........................................................................................................................................
Name : 001.c
Author : SHRUTI VERMA
Description : Write a separate program (for each time domain) to set a interval timer in 10sec and
                10micro second
                a. ITIMER_REAL
                b. ITIMER_VIRTUAL
                c. ITIMER_PROF
Date : 29 Sep 2025
..........................................................................................................................................
*/

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

int i = 0;
void my_handler(int signal) {

    if(signal == SIGVTALRM) {
        i++;

        long ticks = sysconf(_SC_CLK_TCK);

        struct tms t;
        times(&t);
        printf("%d round - System CPU time : %.3f sec\n", i, (double)t.tms_stime/ticks);

        fflush(stdout);
    }
}

int main() {
    signal(SIGVTALRM, my_handler);

    struct itimerval timer;
    timer.it_value.tv_sec = 10;
    timer.it_value.tv_usec = 0 ;

    timer.it_interval.tv_sec = 10;
    timer.it_interval.tv_usec = 10;

    setitimer(ITIMER_VIRTUAL, &timer, NULL);

    while(1) {
         for(int i=0; i<1000000000; i++) {
        }
    }


    return 0;
}

/*----------------------------------OUTPUT----------------------------------------------------------------
1 round - System CPU time : 0.000 sec
2 round - System CPU time : 0.000 sec
3 round - System CPU time : 0.000 sec
4 round - System CPU time : 0.000 sec
5 round - System CPU time : 0.000 sec
6 round - System CPU time : 0.000 sec
7 round - System CPU time : 0.000 sec
8 round - System CPU time : 0.000 sec
9 round - System CPU time : 0.000 sec
10 round - System CPU time : 0.000 sec
11 round - System CPU time : 0.000 sec
12 round - System CPU time : 0.010 sec
13 round - System CPU time : 0.010 sec
14 round - System CPU time : 0.010 sec
15 round - System CPU time : 0.010 sec
16 round - System CPU time : 0.020 sec
17 round - System CPU time : 0.020 sec
*/