A couple of VB6 gotchas

If, like me, you're lucky enough to be maintaining legacy software written in ancient development platforms then you're probably used to workarounds rather than waiting for a product to be fixed.

I came across a couple of particularly scary ones in the VB6 environment concerning the loading and saving of files, I say scary because what it actually loads and saves might not be what you'd expect.

Firstly the loading, once a project is loaded, it seems to have a mindset that it is the only program that could possibly be altering any files so that when you close and reload a module for instance, it doesn't actually read the code from the disk but appears to use a cached version of the file. This is great for speed but bad news if like me, you use third party programs that could alter the source files independent of the VB6 environment.

An example would be Tortoise SVN, where if you have different developers working on a project and you're not using an SCC plug-in then getting the latest version of a source file may be futile if the VB6 environment doesn't actually read it and uses its cached version instead, then you will be working with an out of date source file that after saving, will not incorporate the latest amendments from the others in your team.

Workaround: Short of always using a SCC plug-in, which given what's in the marketplace currently, I'd rather not, it'll be a case of closing VB6 down and re-opening it.

Secondly, on saving. In just about every other language or development platform that I have developed in, when you compile the application to an executable, it automatically saves all the source files that you are working on. VB6 is different, being more of a tokeniser than a real compiler, again it's using what it has cached in RAM to convert to an executable rather than in older 3GLs, a separate compiler program would have been called to parse the source file(s) and hence the need to save them automatically when you compile.

So now I have a DLL that is compiled and managed to check in a source file that doesn't, brilliant.

Workaround: Hit the save button.

The only problem with these workarounds is that you have to remember to do them.