/*------------------------------------------------------------------*/
/* testforkwait.c                                                   */
/* Author: Bob Dondero                                              */
/* The fork and wait system calls.                                  */
/*------------------------------------------------------------------*/

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

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

   printf("Parent process (%d)\n", (int)getpid());

   fflush(NULL);
   iPid = fork();
   if (iPid == -1) {perror(argv[0]); return EXIT_FAILURE; }

   if (iPid == 0)
   {
      /* This code is executed by only the child process. */
      for (i = 0; i < 1000; i++)
         printf("Child process (%d):  %d\n", (int)getpid(), i);

      exit(0);
   }

   /* This code is executed by only the parent process. */

   /* Wait for the child process to terminate. */
   iPid = wait(&iStatus);
   if (iPid == -1) {perror(argv[0]); return EXIT_FAILURE; }

   printf("Child process terminated with status %d.\n",
      WEXITSTATUS(iStatus));

   for (i = 0; i < 1000; i++)
      printf("Parent process (%d):  %d\n", (int)getpid(), i);

   return 0;
}

/*------------------------------------------------------------------*/

/* Sample execution:

$ gcc -Wall -ansi -pedantic testforkwait.c -o testforkwait

$ testforkwait
Parent process (29335)
Child process (29336):  0
Child process (29336):  1
Child process (29336):  2
Child process (29336):  3
...
Child process (29336):  997
Child process (29336):  998
Child process (29336):  999
Child process terminated with status 0.
Parent process (29335):  0
Parent process (29335):  1
Parent process (29335):  2
Parent process (29335):  3
...
Parent process (29335):  997
Parent process (29335):  998
Parent process (29335):  999

*/