/*-------------------------------------------------------------------*/
/* testforkloop.c                                                    */
/* Context switching among concurrent processes.                     */
/*-------------------------------------------------------------------*/

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

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

   printf("Parent process (%ld)\n", (long)getpid());

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

   if (iPid == 0)
   {
      /* This code is executed by only the child process. */
      while (1)
      {
         printf("Child process (%ld):  %d\n", (long)getpid(), i);
         i++;
      }
      exit(0);  /* Should never reach. */
   }

   while (1)
   {
      printf("Parent process (%ld):  %d\n", (long)getpid(), i);
      i++;
   }

   return 0;  /* Should never reach. */
}

/* Sample execution:

$ gcc -Wall -ansi -pedantic -o testforkloop testforkloop.c
$ testforkloop
Parent process (29242) 
Child process (29243):  0 
Child process (29243):  1 
Child process (29243):  2 
...
Child process (29243):  460
Parent process (29242):  0
Child process (29243):  461
Parent process (29242):  1
Child process (29243):  462
Parent process (29242):  2
Child process (29243):  463
Parent process (29242):  3
Child process (29243):  464
Parent process (29242):  4
Child process (29243):  465
...

*/