@ignore
 * Copyright (C) 2000 Martin Str@"omberg <ams@ludd.luth.se>.
 *
 * This software may be used freely so long as this copyright notice is
 * left intact. There is no warranty on this software.
 *
@end ignore

@node _get_fat_size, file system
@findex _get_fat_size
@subheading Syntax

@example
#include <dos.h>

int _get_fat_size( const int drive );
@end example

@subheading Description

This function tries to determine the number of bits used to enumerate
the clusters by the FAT on drive number @var{drive}. 1 == A:, 2 == B:,
etc., 0 == default drive.  

This function will not succeed on DOS version < 4, setting
@code{errno} to @code{ENOSYS}.  It is also known to have trouble
detecting the file system type of disks formatted with a later version
of DOS than the version it is run on.  E. g. floppies with LFN
entries can cause this function to fail or detect the fat size as 16
if used in plain DOS.  

If you are looking for a function that is able to detect other file
systems, perhaps the function @code{_get_fs_type}
(@pxref{_get_fs_type}) can be of use.  

@subheading Return Value

The number of bits used by the FAT (12, 16 or 32).  0 if the drive was
formatted with FAT but of unknown size (NT reports that on FAT16).  
-1 on error. 


@subheading Portability

@portability !ansi, !posix

@subheading Example

@example
#include <stdio.h>
#include <dos.h>

int main(void)
@{
  int size;

  size = _get_fat_size( 'C' - 'A' + 1 );
  if( 0 <= size )
  @{
    printf("The size of FAT on C: is %d bits.\n", size);
  @}

  exit(0);
@}

@end example