Q31511: Variable Passed to Dynamic SUB Changes after Integer Division

Article: Q31511
Product(s): See article
Version(s): 4.00 4.00b
Operating System(s): MS-DOS
Keyword(s): ENDUSER | buglist4.00 buglist4.00b fixlist4.50 | mspl13_basic
Last Modified: 8-DEC-1989

When run from a compiled .EXE program, the dynamic subprogram below
prints an incorrect value for a passed parameter after an unrelated
integer division. The program runs correctly in the QB.EXE editor.

Compiling the program with the BC /D (debug) option or the BC /O
option does not correct the problem.

Microsoft has confirmed this to be a problem in QuickBASIC Versions
4.00 and 4.00b, and in the Microsoft BASIC Compiler Versions 6.00 and
6.00b for MS-DOS and OS/2 (buglist6.00, buglist6.00b). This problem
was corrected in QuickBASIC Version 4.50 and in the Microsoft BASIC
Compiler Version 7.00 (fixlist7.00).

The following is a code example of the subprogram:

DECLARE SUB box (x!, y!)

REM $DYNAMIC
CLS
CALL box(50!, 2!)

REM $STATIC
SUB box (x!, y!)
  PRINT "x! = "; x!
  lf = (70 - x!) \ 2
  dn = (20 - y!) \ 2
  PRINT "x! = "; x!  ' This line prints incorrect value from .EXE program.
END SUB

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