$include (..\lib\compStch.ext)

/*
 *============================================================================
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE
 *
 *  Permission to use for any purpose, modify, copy, and make enhancements
 *  and derivative works of the software is granted if attribution is given to
 *  R.M. Gillmore, dba the ACME Software Deli, as the author
 *
 *  While the ACME Software Deli does not work for money, there is nonetheless
 *  a significant amount of work involved.  The ACME Software Deli maintains the
 *  rights to all code written, though it may be used and distributed as long as
 *  the following conditions are maintained.
 *
 *  1.  The copyright statement at the top of each code block is maintained in
 *      your distribution.
 *  2.  You do not identify yourself as the ACME Software Deli
 *  3.  Any changes made to the software are sent to the ACME Software Deli
 *============================================================================
 */


longFileNameModule:
do;
$if not noID
declare IDString	(*) byte data
	( '@(#)lfModule.p86  $Author: rmgillmore $ $Date:: 2025-05-04 19:35:39#$:', 0 );
$endif

$set ( lfnModule )
$include (..\lib\sysCalls.ext)
$include (..\lib\fileIO.ext)

	declare	longNamesSupported		byte,
			checkPerformed			byte;

lfnSupported:
procedure boolean reentrant public;
	declare	cpuRegisters,
			rootDriveSpecString	(*)	byte data ( 'C:\', 0 ),
			volumeNameString	(32)	byte,
			isSupported				boolean;

	if ( checkPerformed ) then
		isSupported = longNamesSupported;
	else
	do;
		/*
		 *	to discover whether long file name functions are supported, attempt to
		 *	retrieve the volume information.  If 0 is returned in the AL register,
		 *	long file names are not supported.
		 *
		 *	So, why are we using the "retrieve volume information" function?
		 */

		wordRegs.Ax = 71a0h;
		wordRegs.Ds = selector$of( @rootDriveSpecString );
		wordRegs.Dx = offset$of( @rootDriveSpecString );
		wordRegs.Es = selector$of( @volumeNameString );
		wordRegs.Di = offset$of( @volumeNameString );
		wordRegs.Cx = size( volumeNameString );

		call int86( DOS_CALL, @wordRegs );
		if ( carryClear( @wordRegs ) and ( wordRegs.Ax = 71a0h ) ) then
			isSupported = True;
		else
			isSupported = False;

		longNamesSupported = isSupported;
		checkPerformed = True;
	end;

	return ( isSupported );
end lfnSupported;

end longFileNameModule;