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- This document describes the API changes introduced in version 0.99.12 of PTCPas
- Since version 0.99.12, most PTCPas classes have been made descendants of
- TInterfacedObject and are now only accessible via interfaces. The reason for
- this change is to provide automatic memory management via reference counting for
- the PTC core objects, so that they are freed automatically, once they're no
- longer in use, without causing any memory leaks.
- Unfortunately, this breaks existing code. However, it's relatively easy to fix
- it and the purpose of this document is to explain how. Here's a basic summary
- of the changes that need to be made:
- 1) in your source code, replace "TPTCSomething.Create" with
- "TPTCSomethingFactory.CreateNew" (where 'Something' will correspond to one of
- those, depending on which objects are used in your program: Area, Color,
- Console, Event, Format, KeyEvent, Mode, MouseButtonEvent, MouseEvent, Palette,
- Surface and Timer)
- 2) replace "TPTCSomething" with "IPTCSomething" (where 'Something' = an object
- from point #1)
- 3) try compiling your code and you'll probably get some errors. Remove every
- call to .Free that fails with a compilation error, since it's no longer needed -
- PTC core objects are freed automatically when their reference count reaches
- zero.
- 4) if you are using FreeAndNil, be extra careful! Since it accepts an untyped
- var parameter (bad design coming from Delphi), it will not cause a compilation
- error, if you are using it on an interface, but you will instead get a crash at
- runtime. Sadly, there's not much you can do, besides checking every call to
- FreeAndNil and replacing it with ":= nil" when you're using it on a PTC core
- object.
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