Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!rochester!rit!ritcv!iav1917
From: iav1917%ritcv@cs.rit.edu (alan i. vymetalik)
Newsgroups: comp.sys.ibm.pc
Subject: Re: switchar character under MSDOS
Keywords: '/' '-' source code assembler
Message-ID: <1006@cs.rit.edu>
Date: 24 Mar 89 01:13:43 GMT
References: <6202@bsu-cs.UUCP> <1150@frog.UUCP>
Sender: news@cs.rit.edu
Reply-To: iav1917%ritcv@cs.rit.edu (alan i. vymetalik)
Organization: Rochester Institute of Technology, Rochester, NY
Lines: 66

In article <1150@frog.UUCP> rmk@frog.UUCP (Rick Kelly) writes:
>
>	There are two undocumented library routines in Turbo C for setting
>and inspecting the switch character.  I don't have the information close at
>hand but I will post it tomorrow.
>
>Rick Kelly

   Well, I can't recall what the routines are in Turbo C either.  However,
   changing the switch character is as easy as the example that follows.
   It's in TurboPascal, but it's easily converted.  Academically it may be
   fun, but many programs do not properly check the switch character and
   instead check for particular character on the parameter line.  Caveat
   Emptor, I suppose...

   Enjoy the routine,
   Alan

----------------------------------------------------------------------------
{
   SWCHAR.PAS
   
   SWCHAR will set the MS-DOS switch character (normally a "/") to
   any character passed as a parameter to the program.  I.e.:
   SWCHAR T will set the switch character to "T".  This routine uses
   the "undocumented" MS-DOS function #35.  The code should be self-
   explanatory.

   Language: TurboPascal V5.0, O/S: MS-DOS V2.11 and above.
}

Uses
   DOS;

Var
   s : string[1];
   r : Registers;

begin { swchar }

   if paramcount = 1 then
      begin
         { Use the letter from the command 
           line as the switch character }
         s    := paramstr(1);
         r.ax := $3701;
         r.dx := ord(s[1]);
         msdos(r);
      end;
          
   { Show current or modified switch character }
   r.ax := $3700;
   msdos(r);
   writeln('The switch character is ',chr(r.dx and $00FF));

end.  { swchar }

----------------------------------------------------------------------------
   Mail:  Alan I. Vymetalik, Prism Software Designs, 8 Barn Swallow Lane
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