#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#include <errno.h>
 
 
int main(void)
{
  int shmm;
  volatile int counter = 0;
  volatile int* address;

  shmm = open("/dev/shmm", O_RDWR);
  if (shmm < 0) {
    printf("File not found\n");
    return 1;
  }
 
  address = mmap(0, getpagesize(), PROT_WRITE | PROT_READ,
                 MAP_PRIVATE , shmm, 0);
 
  if (address == (void *)-1) {
      printf(stderr,"mmap(): %s\n",strerror(errno));
      exit(1);
  }

  while(1) {
    *address = counter;
    write(shmm, &counter, sizeof(counter));
    counter++;
  }

  munmap((void*)address,getpagesize());
  close(shmm);
}