Unsigned Integers And Visual Basic

Update: the information in this post has been superseded by the information from this post: Device context handles and signed/unsigned integer. It is no longer required to use unsigned integers with the ActiveX edition, this is handled internally by the library.

In version 7.25 of Quick PDF Library we made a change to the API which made the use of unsigned integers necessary. Unfortunately not all versions of programming languages support unsigned integers. In this particular case Visual Basic 6 and earlier versions do not support unsigned integers, while Visual Basic .NET and newer versions do.

Although VB6 was released over 10 years ago it still has a strong following and quite a few VB6 programmers use Quick PDF Library. This being the case we’ve come up with an easy workaround which will enable VB6 programmers to continue using all of the functions in Quick PDF Library.

We’re now providing a TLB file along with the ActiveX edition that handles the unsigned integers. The TLB file is only used at compile time so you won’t need to distribute it with your executable, but you will need to distribute the ActiveX as per usual.

The TLB file for Quick PDF Library 7.25 can be downloaded from here and will be included in all future installers.

Instructions for using the TLB file:

1. Register the ActiveX on your machine as per usual
2. Open your VB6 project
3. Go to Project > References > Browse…
4. Add the ‘QuickPDFAX0725VB.tlb’ file
5. Compile

As you are adding the TLB file as the reference it is not necessary to add the ActiveX file as a project reference because the TLB file interfaces with the ActiveX through the registry.

Please note: if you do not use the GetCanvasDC, DARenderPageToDC or RenderPageToDC functions then you won’t run into any issues if you choose not to use the TLB file. The unsigned integers are currently only used with these functions.