Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!usc!ucsd!hub.ucsb.edu!6600m00n
From: 6600m00n@ucsbuxa.ucsb.edu (Steelworker)
Newsgroups: comp.os.msdos.programmer
Subject: Re: Help Generating an Interrupt
Message-ID: <7082@hub.ucsb.edu>
Date: 10 Nov 90 02:04:52 GMT
References: <0093F67F.C5AB8C20@router.jhuapl.edu>
Sender: news@hub.ucsb.edu
Reply-To: 6600m00n@ucsbuxa.ucsb.edu
Organization: Ghostwheel Redevelopment Agency
Lines: 28
In-reply-to: tcs@router.jhuapl.edu's message of 8 Nov 90 17:43:41 GMT

In article <0093F67F.C5AB8C20@router.jhuapl.edu> tcs@router.jhuapl.edu writes:

     In reading an old issue of Dr. Dobbs these past few days (I was sick) I 
   came upon an undocumented dos call 52h. This is supposed to produce a far 
   pointer to a drive table which contains another pointer to another drive 
   table which contains the Path followed by a word that contains one of four 
   values; Networked drive, Available, Joined or Subst'd. The article (and a 
   followup letter) said that you had to place 52h into AH and retrieve the 
   far pointer from BS:?? (I think this is correct, but beside the point). 

     The problem I'm having is how to generate that call. Do I generate 52h? 
   13h? 21h? or some other interrupt? 
-The answer is to use the function  int86x functions.  You pass it
some structures of what the various registers are supposed be on the 
interrupt.
The interupt number you want is 21h ( first paramater to the function).
The rest of the info you can find in the online help.

      Oh and I looked in Inter590 and (of course) it's not documented! (Gee, I 
      never would have guessed :-)
-Once you find out what it does exactly, mail them and tell what you
find. 
     
   Carl Schelin
   tcs@router.jhuapl.edu

-Rob Blair
6600m00n@ucsbuxa.ucsb.edu