/*
 * A simple program to illustrate the work of a pair of pipes,
 * a process can write to the pipe and read directly back from it.
 */
#include <stdio.h>
#include <unistd.h>
#include <string.h>

#define BUFFER_SIZE 32
#define READ_END    0     // read 0 and write 1 can't be chosen randomly
#define WRITE_END   1

int main(int argc, char * argv[])   {

  char sent_msg[BUFFER_SIZE] = "Greetings";
  char read_msg[BUFFER_SIZE];
  pid_t pid;
  int fd[2];
  int amt_read;   // number of bytes read
  char c;

  /* create the pipe */
  if (pipe(fd) == -1) {
     fprintf(stderr," pipe failed \n");
     return -1;
  }

  printf("fd[0] %u  fd[1] %u\n", fd[0], fd[1]);

  /* write to the pipe */
  write(fd[WRITE_END], sent_msg, strlen(sent_msg));

  /* read the message */
  amt_read = read(fd[READ_END], read_msg, BUFFER_SIZE);
  read_msg[amt_read] = 0;  // terminate the string
  printf("read %s\n", read_msg);

  return 0;
}