Xref: news-dnh.mv.net comp.os.msdos.djgpp:2874
Path: news-dnh.mv.net!mv!news.sprintlink.net!wizard.pn.com!mozo.cc.purdue.edu!purdue!oitnews.harvard.edu!news.sesqui.net!rice!news!sandmann
From: Charles Sandmann <sandmann AT clio DOT rice DOT edu>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Windows 95 long filenames
Date: Thu, 26 Oct 1995 07:58:52 CDT
Organization: Rice University, Houston, Texas
Lines: 13
References: <DH1vAG DOT Fr8 AT jade DOT mv DOT net>
Reply-To: sandmann AT clio DOT rice DOT edu
Nntp-Posting-Host: clio.rice.edu
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Dj-Gateway: from newsgroup comp.os.msdos.djgpp

> The book `Undocumented DOS' (by Andrew Schulman et al, publ. Addison-Wesley)
> says that various DOS interrupts `AH=0x71, AL=0xXX, int21' do the same as the
> corresponding `AH=0xXX, int21' but with Windows95 long filenames instead of
> xxxxxx.xxx DOS filenames. How can a program running under any version of DOS
> find if the (computer that it is on) has these `AH=0x71, int21' interrupts?

See the file src/libc/dos/lfn/_use_lfn.c in the V2B3 (or lfn_sbrk.zip) 
distributions for a detection example which I know works.

In some cases it's as simple as changing to the 0x71 interrupt form, but
in other cases MS has added new register arguments which you must specify
properly or you will get the wrong behavior.  The above source distributions
also give examples of all the open/rename/delete/etc type calls.