@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_fs_type, file system
@findex _get_fs_type
@subheading Syntax

@example
#include <dos.h>

int _get_fs_type( const int drive,
                  char *const result_str );
@end example

@subheading Description

This function tries to extract the file system type of the drive
number @var{drive}, 1 == A:, 2 == B:, etc., 0 == default drive.  It
does this by calling INT21, AX=0x6900, Get Disk Serial Number (sic!),
which returns, among other things, an eight character field which is
set while formatting the drive. Now, this field can be set to whatever
the formatting program wishes, but so far every FAT formatted drive
has returned a string starting with "FAT".  

If successful the result is put in @var{result_str} which must be at 
least 9 characters long.  If unsuccessful @code{errno} is set.  

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 floppy as
FAT16 if used in plain DOS.  

If you are interested in which kind of FAT file system that is in use
try the function @code{_get_fat_size} (@pxref{_get_fat_size}) which
will reliably detect the right kind of FAT file system.  

@subheading Return Value

0 if the file system type was extracted successfully; otherwise -1.  

@subheading Portability

@portability !ansi, !posix

@subheading Example

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

int main(void)
@{
  char buffer[9];

  if( ! _get_fs_type( 3, buffer ) )
  @{
    printf("The file system on C: is '%s'.\n", buffer);
  @}

  exit(0);
@}

@end example