dmake/msdos/switchar.c

   1 /* RCS  $Id: switchar.c,v 1.1.1.1 2000-09-22 15:33:27 hr Exp $
   2 --
   3 -- SYNOPSIS
   4 --      switch char query.
   5 --
   6 -- DESCRIPTION
   7 --      Get the current value of the command line switch char.  Only useful
   8 --      in a DOS environment, otherwise we #define it to be '-'.
   9 --
  10 -- AUTHOR
  11 --      Dennis Vadura, dvadura@dmake.wticorp.com
  12 --
  13 -- WWW
  14 --      http://dmake.wticorp.com/
  15 --
  16 -- COPYRIGHT
  17 --      Copyright (c) 1996,1997 by WTI Corp.  All rights reserved.
  18 --
  19 --      This program is NOT free software; you can redistribute it and/or
  20 --      modify it under the terms of the Software License Agreement Provided
  21 --      in the file <distribution-root>/readme/license.txt.
  22 --
  23 -- LOG
  24 --      Use cvs log to obtain detailed change logs.
  25 */
  26 #if defined(_MSC_VER)
  27 #include <stdlib.h>
  28 #endif
  29 #include <dos.h>
  30 #include <stdio.h>
  31 #include "stdmacs.h"
  32
  33 getswitchar()/*
  34 ===============
  35    Try the environment first.  If you don't find SWITCHAR there, then use
  36    the DOS call.  The call is undocumented, and doesn't work for DOS versions
  37    4.0 and up, so the check of the environment will fix that. */
  38 {
  39 #if defined(__MSDOS__) || defined(M_I86)
  40    union REGS rg;
  41    static char *_env_switchar = NIL(char);
  42
  43    if( _env_switchar != NIL(char) ||
  44        (_env_switchar = (char *)getenv("SWITCHAR")) != NIL(char) )
  45       return(*_env_switchar);
  46
  47    rg.h.ah = 0x37;      /* switch char request */
  48    rg.h.al = 0;         /* get (not set) */
  49
  50    intdos(&rg, &rg);
  51    return (rg.h.dl);
  52 #endif /* M_I86 */
  53
  54    return ('-');
  55 }