Tuesday, May 19, 2009


VB6 doesn't seem to be able to specify that a Double contains MAXDOUBLE, MINDOUBLE, +INFINITY, -INFINITY or NaN. (I could be wrong on that as there may be some undocumented feature hiding in there somewhere.)

Anyway, I came up with a way of storing these values into Doubles so that they could be used in a Complex Numbers library I've been writing.

Essentially, I create an 8 byte array, load it up with the relevant values, and then, using API calls and the VarPtr function, store the contents of the array into the storage used by the Double.

Here's the code. First the declarations.

Then the routine that does the work.

Finally, a slice out of the Complex Numbers project demonstrating the use of some of these declarations.


© Copyright Bruce M. Axtens, 2009

Thursday, May 14, 2009

[VB6]Searching an ActiveX/COM object for a method

This article was first posted by me on StackOverflow in response to my own question, "How do I search an ActiveX/COM object for a method?". This article is an edited version of the original.

"After Googling around not quite finding what I wanted, I remembered the
Edanmo site which got me thinking about TLBINF32.DLL, downloading Microsoft's TLBINF32.CHM and reading up on GetMembersWithSubStringEx.

Below is the implementation of it (done in VB6 with a reference to TLBINF32.DLL), some demo VBScript and output, and the wrapping of that functionality in some VBA.

VBScript demo. The above code was included in my StdLib DLL in the Registry coclass.

Output from the demo (script was run in SciTE).

Finally, the VBA code. A cell has a symbol in it and this routine finds it or returns an error string. (reg. in this case refers to the Registry coclass in the StdLib.DLL)

Hmm ... no error checking. Should fix that.

© Copyright Bruce M. Axtens, 2009