VB Forum / COM / October 2005

Hi,

  My VB6 (SP6)  app produces an Overflow error and bombs. I use Win XP
(Sp2).

1) Program has Option Explicit. So every variable is typed.
2) Program works fine on one computer, but not on another!
3) Error is intermittent.
4) Sometimes it overflows even on VB timer function.

  I am using a dll that was created from another program. In the calling
statement, there are 13 output arguments (x1,y1,z1,...) defined as Variant.
They are arrays with no priory knowledge of their size. And there are
several input arguments (in1,in2...) typed as double.

Dim b as variant
Dim x1 as variant
Dim y1 as variant
......

   call subroutine(13,
b,x1,y1,z1,x2,y2,z2,x3,y3,z3,x4,y4,z4,in1,in2,in3,in4,...)

   These arrays used to plot a 3D graph:

   with Graph3D

       for i=1 to ubound(a1,1)
           PlotXYZ x1(i,1),y1(i,1),z1(i,1),0
       next
       for i=1 to ubound(a1,1)
           PlotXYZ x2(i,1),y2(i,1),z2(i,1),1
       next
       for i=1 to ubound(a1,1)
           PlotXYZ x3(i,1),y3(i,1),z3(i,1),2
       next
       for i=1 to ubound(a1,1)
           PlotXYZ x4(i,1),y4(i,1),z4(i,1),3
       next
       .autorange

    end with

    I believe the overflow is caused by somewhere in these for loops. If I
remove the last two or three loops it goes away! What the hell is going on?

    Is there a way to detect/trap overflow? I run MS code advisor, it is
useless. Any help greatly be appreciated. Please help.

Cem