/*------------------------------------------------------------------*/
/* testforkloop.c                                                   */
/* Author: Bob Dondero                                              */
/* Context switching among concurrent processes.                    */
/*------------------------------------------------------------------*/

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

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

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

   return 0;
}

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

/* Sample execution:

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

$ testforkloop
Parent process (27915)
Child process (27916):  0
Child process (27916):  1
Child process (27916):  2
...
Child process (27916):  486
Child process (27916):  487
Child process (27916):  488
Parent process (27915):  0
Parent process (27915):  1
Parent process (27915):  2
...
Parent process (27915):  997
Parent process (27915):  998
Parent process (27915):  999
Child process (27916):  489
Child process (27916):  490
Child process (27916):  491
...
Child process (27916):  997
Child process (27916):  998
Child process (27916):  999

*/