tcs@router.jhuapl.edu (11/09/90)
Hello everyone, 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? Information: I'm using TC++ 1.01 and 3.30 IBM PC-Dos on a 386-25. I've been working with C for a few years and BASIC before that. I have had very very limited instructions on asm but am planning with TAsm. You can E-Mail or respond as I get both. I want to thank you for any information you can give me. Oh and I looked in Inter590 and (of course) it's not documented! (Gee, I never would have guessed :-) Thanks again... Carl Schelin tcs@router.jhuapl.edu
6600m00n@ucsbuxa.ucsb.edu (Steelworker) (11/10/90)
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.eduts@uwasa.fi (Timo Salmi) (11/10/90)
In article <7082@hub.ucsb.edu> 6600m00n@ucsbuxa.ucsb.edu writes: >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 ... much deleted ... > > 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. You'll find some useful information on Int $52 in Michael Tischer (1990), Turbo Pascal Internals, Abacus, pp. 70-71. ................................................................... Prof. Timo Salmi (Moderating at anon. ftp site 128.214.12.3) School of Business Studies, University of Vaasa, SF-65101, Finland Internet: ts@chyde.uwasa.fi Funet: gado::salmi Bitnet: salmi@finfun
Ralf.Brown@B.GP.CS.CMU.EDU (11/10/90)
In article <7082@hub.ucsb.edu>, 6600m00n@ucsbuxa.ucsb.edu (Steelworker) wrote: } 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. As I've already replied privately, it's already in the interrupt list (about 850 lines worth). Carl just missed it because of his confusion about which call to make. -- UUCP: {ucbvax,harvard}!cs.cmu.edu!ralf -=- 412-268-3053 (school) -=- FAX: ask ARPA: ralf@cs.cmu.edu BIT: ralf%cs.cmu.edu@CMUCCVMA FIDO: 1:129/3.1 Disclaimer? | I was gratified to be able to answer promptly, and I did. What's that? | I said I didn't know. --Mark Twain