#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#include <stdio.h>
#include <string.h>

static const char *file = "mmap_file";
#define FILE_SIZE 8192

int main ()
{
   int i,fd;
   unsigned char *map;

   if ((fd = open ("mmap_file",O_RDWR|O_CREAT)) < 0) {
       printf("Could not open file %s\n",file);
       perror (NULL);
       exit (1);
   }

    map = mmap (NULL,
	       FILE_SIZE,
	       PROT_READ | PROT_WRITE,
	       MAP_SHARED,
	       fd,
	       0);

   if (map == MAP_FAILED){
       printf("Could not mmap file %s\n",file);
       perror (NULL);
       exit (1);
   }
   
   printf("mmap of file %s OK\n",file);

   munmap (map,FILE_SIZE);
   close (fd);
   exit (0);
}