Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!cs.utexas.edu!oakhill!val!ben
From: ben@val.UUCP (Ben Thornton)
Newsgroups: comp.sys.ibm.pc
Subject: Re: DOS "Critical Section Flag"
Message-ID: <353@val.UUCP>
Date: 29 Jun 89 01:38:44 GMT
References: <23020@santra.UUCP>
Organization: Video Associates Labs Inc. - Austin, Tx
Lines: 19

c37189h@saha.hut.fi writes:

>Someone wanted to know when it is safe to access dos. (I think it was in this
>newsgroup) So, here comes one way to ditect safety:

Describes Dos Int 21H Function 43H...

>This seems quite a complex way of detecting safety to me! I wonder if anyone
>knows a better way to do it. (In case anyone does please, e-mail to me!)

Actually, I think the only SAFE thing to do is intercept Int 21H and have the
handler maintain a status flag.  Your routines that handle file I/O within
your TSR can then test that flag.  I believe it is more reliable and less
hassle in the long run.
-- 

Ben Thornton             packet:  WD5HLS @ KB5PM
Video Associates Labs      uucp:  ...!cs.utexas.edu!oakhill!val!ben
Austin, TX              fidonet:  1:382/40 - The Antenna Farm BBS