Compiler Conundrums!

 BBS: Inland Empire Archive
Date: 11-23-92 (14:49)             Number: 349
From: JOHN GALLAS                  Refer#: NONE
  To: MIKE KERR                     Recvd: NO  
Subj: Compiler Conundrums!           Conf: (2) Quik_Bas

MK>The problem I'm having now, is similar, yet not.  Sorry, I won't be
MK>cryptic any more! :-)   I have just written a program that will print

MK>C:\QBASIC\PP.BAS
MK>Which is EXACTLY what I want.  I get this from MID$(COMMAND$,4).  So,
MK>what's the problem?  When I compile the program, all that gets read in
MK>is:
MK>QBASIC\PP.BAS

<etc etc>

Heres a routine that'll use interrupts to read in the command line
entered from DOS.  It shouldn't take off any characters, and it even
preserves upper/lower case.


'=================================================================
'Date: 04-11-91
'From: BRENT ASHLEY
'Subj: ORIGINAL COMMAND LINE; preserving lower case
'Conf: QBASIC (62)

'The command line as entered at the DOS prompt, in all its mixed-case
'splendour, is found at offset &H81 of the program's PSP (Program Segment
'Prefix), with the length of the command string at offset &H80 of the
'PSP.
'
'Finding your PSP from within QuickBASIC entails Interrupt calls.
'   ~~~~~~~~~
'That same area of the PSP, however, is also the default disk transfer
'area for the program (or is it the default File Control Block? - I don't
'have my references handy) At any rate, I suspect QB always defines its
'own DTAs and FCBs, so the data won't be overwritten, but this cannot
'always be guaranteed.  It would be best, therefore, if you were to get
'this info, to get it as early in the program's execution as possible,
'especially before any file I/O.
'======================================================================

DECLARE FUNCTION CmdLine$ ()
DEFINT A-Z
' $INCLUDE: 'qb.bi'

PRINT "Here's the original command line:"
PRINT "["; CmdLine$; "]"

END

FUNCTION CmdLine$
  '
  ' CmdLine - returns original command line
  '
  DIM Regs AS RegType
  STATIC CmdLen, CmdBuild$, i
  '
  ' DOS Interrupt 21h service 62h returns the segment
  ' address of the running program's PSP in the bx register.
  '
  Regs.ax = &H6200
  CALL Interrupt(&H21, Regs, Regs)
  DEF SEG = Regs.BX
  '
  ' The command line's length is found at offset 80h of the PSP
  ' and the actual command line starts at 81h
  '
  CmdBuild$ = ""
  CmdLen = PEEK(&H80)
  FOR i = 1 TO CmdLen
    CmdBuild$ = CmdBuild$ + CHR$(PEEK(&H80 + i))
  NEXT
  '
  ' restore BASIC data segment and return data
  '
  DEF SEG
  CmdLine$ = CmdBuild$
END FUNCTION

The only problem is, you can't change the command line from within the
QB environment, but if you're always running from an exe, it'll work
fine.

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