#define _XOPEN_SOURCE 600

#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>

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

  if (argc != 2) {
    printf ("need a filename arg\n");
    exit (1);
  }
  

  fd = open (argv[1], O_RDWR);
  if (fd <0) {
    perror ("unable to open file");
    exit (1);
  }

  ret = posix_fadvise (fd, 0, 0, POSIX_FADV_DONTNEED);
  if (ret != 0) {
    printf ("posix_fadvise failed: %d, %s\n", ret, strerror (ret));
    exit (1);
  }
  return 0;
}