#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>

int main (int argc, char *argv[]) {
   pid_t childpid = 0;
   int i, n;

   if (argc != 2){      /* check number of command-line arguments */
      fprintf(stderr, "Usage: %s processes\n", argv[0]);
      return 1;
   }
   n = atoi(argv[1]);
   for (i = 1; i < n; i++)
      if ((childpid = fork()) <= 0)
         break;
   for( ; ; ) {
      childpid = wait(NULL);
      if ((childpid == -1) && (errno != EINTR))
        break;
   }
   fprintf(stderr, "I am process %ld, my parent is %ld\n",
                   (long)getpid(), (long)getppid());
   return 0;
}