#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/shm.h>
#include <sys/mman.h>
#include <sys/stat.h>

int main()
{
  const int SIZE = 4096;
  const char *name = "OS";

  int shm_fd;
  void *ptr;

  shm_fd = shm_open(name, O_RDONLY, 0666);
  ptr = mmap(0, SIZE, PROT_READ, MAP_SHARED, shm_fd, 0);
  printf("%s", (char *)ptr);
  shm_unlink(name);
}