How can I determine a diskette format and if a disk is in a drive?

Let's have a snippet from one of my functions:

The 'ifdef M_I386's mean CSet/2

--- snip ---

EXPORT int GetFileSysAttach ( char cDrv, PVOID pInfo, UnsInt cbInfo )
{
CHAR szFileSys [4];

  szFileSys [0] = (CHAR) toupper ( cDrv );
  szFileSys [1] = ':';
  szFileSys [2] = '\0';

  DosError ( EXCEPTION_DISABLE );

#ifdef M_I386
  Errno = DosQueryFSAttach ( szFileSys, 0, FSAIL_QUERYNAME, pInfo, &cbInfo );
#else
  Errno = DosQFSAttach ( szFileSys, 0, FSAIL_QUERYNAME, pInfo, &cbInfo, 0L );
#endif

  DosError ( EXCEPTION_ENABLE );
  return Errno ? -1 : 0;
}


EXPORT	int	GetFileSysInfo ( PSZ pszFileSys, PFSysInfo pfsi )
{
USHORT	idDrv;
FSALLOCATE fsal;
FSINFO	fsinfo;
#ifdef M_I386
PFSQBUFFER2 fsq = NULL;
#else
PFSQBUFFER  fsq = NULL;
PUSHORT     pus;
#endif
CHAR    hbuf [L_FILENAME];
PCHAR   pch;
#ifndef _MT
BOOL    fProt = ProtectedMode ();
#else
#define fProt TRUE
#endif

  idDrv = tolower ( *pszFileSys ) - ('a' - 1);

  DosError ( EXCEPTION_DISABLE );

  if ( ! (Errno = DosQFSInfo ( idDrv, 1, (PBYTE) &fsal, sizeof ( fsal ) )) )
    Errno = DosQFSInfo ( idDrv, 2, (PBYTE) &fsinfo, sizeof ( fsinfo ) );

  DosError ( EXCEPTION_ENABLE );

  if ( Errno )
  {
    if ( Errno == ERROR_NO_VOLUME_LABEL )
      memset ( &fsinfo, 0, sizeof (fsinfo) );
    else
      return -1; // No disk inserted
  }

  if ( fProt )
  {
    if ( GetFileSysAttach ( (CHAR) (idDrv + 'a' - 1), hbuf, L_FILENAME ) )
      return -1;

#ifdef M_I386
    fsq = (PFSQBUFFER2) hbuf;
#else
    fsq = (PFSQBUFFER) hbuf;
#endif
  }

  DosError ( EXCEPTION_ENABLE );

  ...

--- snap ---

I think it's more than you want, the fsal-struct contains the size information, but I think if you want to retrieve ALL information about a logical drive that's what you need.

Credit: Rainer Prem