/*
This program illustrates the use of fork and pipes for interprocess
communication.  It sets up a client-server relationship between processes.
The parent process acts as server, the children clients.
*/
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<sys/types.h>
#include<unistd.h>
#include "simpleipc.c"

void parentfun(int pipe);
void childfun(int pipe);

int main()
{ int i, j;
  int pfd[2];      // global ipc pipe.
  pid_t procid;    // used to distinguish parent/child after fork
  i = pipe(pfd);   // create pipe
  if (i!=0) { printf("pipe creation failed\n"); exit(1); }
  
  procid = fork();  // create child process
  
  if (procid == 0)  // child
    childfun(pfd[1]);
  else parentfun(pfd[0]); // parent;
  exit(0);
}
 
/* The parent serves fibonacci numbers to child */

void parentfun(int pipe)
{  int a, b, x;
   a = 0; b = 1;
   while(1<2)
     {
       printf("server ready for next client request ...\n");
       entry(pipe,4,&b);
       //       entry(pipe,4,iptovoidp(&b));
       x = b;    // compute next fibonacci number to get ready.
       b = a+b;
       a = x;
       for(x=0;x<25000000;x++) {}  // simulated delay
     }
}  // parentfun


void childfun(int pipe)
{ int i, x;
  pid_t myid, parentid;

  myid = getpid();
  parentid = getppid();
  printf("My process id is %d, and my parent's is %d\n",myid,parentid);
  for(i=0;i<10;i++)  // get first 10 fibs from server
    {
	//       request(pipe,sizeof(int),iptovoidp(&x));
       request(pipe,sizeof(int),&x);
       printf("I got %d from the parent process\n",x);
    }
  close(pipe);
  printf("process %d exiting.\n",myid);
} // childfun