Delphi Memory Management

Question

I haven't been able to find the answers to a couple of my Delphi memory management questions. I could test different scenarios (which I did to find out what breaks the FreeAndNil method), but its takes too long and its hard! But seriously, I would also like to know how you all (Delphi developers) handle these memory management issues.

My Questions (Feel free to pose your own I'm sure the answers to them will help me too):

1. Does FreeAndNil work for COM objects? My thoughts are I don't need it, but if all I need to do is set it to nil than why not stay consistent in my finally block and use FreeAndNil for everything?

2. Whats the proper way to clean up static arrays (myArr : Array[0..5] of TObject). I can't FreeAndNil it, so is it good enough to just set it to nil (do I need to do that after I've FreeAnNil'd each object?)?

Thanks Guys!

Answer 1

COM objects are referenced via Interfaces, which you don't need to do anything to free. The compiler takes care of the necessary reference-counting logic to make sure the COM object will be disposed of at the right time.

As for static arrays, (or dynamic arrays, for that matter,) they don't need to be freed by you either. If they contain objects then the objects have to be freed at the appropriate time, but the arrays don't.

Also, never use FreeAndNil on anything that's not an object reference. Using it with interfaces or other variables can corrupt memory. It's best to never use it (use Free instead) unless you're dealing with an object that you need to free and then reuse later.