MIO file vs. mmap()ed file

file.c

#include <stdio.h>

#include "mio/mio.h"

int
main (int     argc,
      char  **argv)
{
  int ret = 0;
  int i;
  
  for (i = 1; ret == 0 && i < argc; i++) {
    FILE *fp;
    
    if (! (fp = fopen (argv[1], "r"))) {
      perror ("fopen()");
      ret = 1;
    } else {
      MIO *mio = mio_new_fp (fp, NULL);
      
      if (! mio) {
        perror ("mio_new_fp()");
        ret = 2;
      } else {
        while (! mio_eof (mio)) {
          int c = mio_getc (mio);
        }
        mio_free (mio);
      }
      fclose (fp);
    }
  }
  
  return ret;
}

mmap.c

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

#include "mio/mio.h"

int
main (int     argc,
      char  **argv)
{
  int ret = 0;
  int i;
  
  for (i = 1; ret == 0 && i < argc; i++) {
    int fd;
    
    if ((fd = open (argv[1], O_RDONLY)) < 0) {
      perror ("open()");
      ret = 2;
    } else {
      size_t len = lseek (fd, 0, SEEK_END);
      void *map = mmap (NULL, len, PROT_READ, MAP_PRIVATE, fd, 0);
      
      if (map == MAP_FAILED) {
        perror ("mmap()");
        ret = 3;
      } else {
        MIO *mio = mio_new_memory (map, len, NULL, NULL);
        
        if (! mio) {
          perror ("mio_new_memory()");
          ret = 4;
        } else {
          while (! mio_eof (mio)) {
            int c = mio_getc (mio);
          }
          mio_free (mio);
        }
        
        munmap (map, len);
      }
      close (fd);
    }
  }
  
  return ret;
}