forkexec.c

#include <unistd.h>
#include <time.h>
#include <stdio.h>

double sec(void) {
    struct timespec tv;

    clock_gettime(CLOCK_MONOTONIC, &tv);

    return tv.tv_sec + tv.tv_nsec / (1000000000.0);
}


int main()
{
    int nloop = 1024, li;
    double t0 = sec(), t1;

    for (li=0; li<nloop; li++) {
        int pid = fork();
        int st;

        if (pid == 0) {
            execlp("./exit2",
                   "./exit2",
                   NULL);
        }

        wait (&st);
    }

    t1 = sec();

    printf("%f\n", (t1-t0)/nloop);
}