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

/**
 * This program shows what can happen when multiple processes
 *  try to indiscrimately share a file descriptor, in this
 *  stdout.
 * For best results, pipe the output of the file into more,
 *
 *       ./sharedOut | more
 *
 * What determines how many characters are output by each process
 *  before the next process takes over?
 */

int main()
{
   pid_t pid;
   char s[] = "||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||";
   char *p = NULL;

   pid = fork();        /* fork another process */

   if (pid < 0)         /* Forking error! */
      {   exit(-1);   }
   else if (0 == pid)   /* Child process */
     {
       // Child replaces string of |'s with *'s.
       p = s;
       while (*p)
	 *(p++) = '*';
       
       // Go into infinite loop printing out string.
       while (1)
	 {
	   p = s;
	   while(*p)
	     putchar(*(p++));
	   putchar('\n');
	 }
       exit(0);
     }
   else                 /* pid > 0: Parent process */
     {   
       // Go into infinite loop printing out string.
       while (1)
	 {
		   p = s;
	   while(*p)
	     putchar(*(p++));
	   putchar('\n');
	 }
     }
}