mappedmem.c

  int    fd;
  char * mapped_memory;

  /**
   * Open a file and map it to memory,
   * once it is mapped to memory we can close
   * the file because we have access.
   */
  fd = open(argv[1], O_RDWR | O_CREAT);
  mapped_memory = mmap(NULL, MAX, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
  close(fd);

  if(strncmp(mapped_memory, "exit", 4) == 0)
    mapped_memory[0] = '\0';

  /** If Reader **/
  if (!strcmp(argv[2], "read")) {
    while (1) {
      mapped_memory[MAX - 1] = '\0';
      printf("%s", mapped_memory);
      if(strncmp(mapped_memory, "exit", 4) == 0)
	exit(1);
      fflush(stdout);
      sleep(1);
    }

  /** If Writer **/
  } else if (!strcmp(argv[2], "write")) {
    while (strncmp(mapped_memory, "exit", 4) != 0)
      fgets(mapped_memory, MAX, stdin);
  }