In Delphi is there a point to declare a parameter of type object as const?

Question

I know the benefits of const parameters for simple types and strings in Delphi. But what about a const TStrings? Since a const TStrings parameter can have its items (content) changed, what's the point of declaring a const TStrings parameter for example? This applies to any object too.

Answer 1

The const applies only to the pointer to the TStrings object, not to the TStrings object itself. So it really makes little difference on non-ARC based platforms, especially if the code does not try to change where the pointer is pointing to. It's only real use is to document the intention of the parameter.

But, the const can make a BIG difference on ARC-based platforms. It disables implicit reference counting on the object that is passed to the parameter (just as const does for string and interface parameters).