Mixing garbage collected framework with normal code

I know my way around Objective-C and I have experience with garbage collection from .NET, although I never used it in objective-c. I write my code without using it.

Now I'm thinki开发者_运维知识库g about using one of the frameworks (Blocks) which is available as GC-only. My question is - can I still use the framework without any changes to my current non-GC code and without using GC myself?

A process is either GC or non-GC. That is, all Objective-C will either always be GC'd or will never be GC'd. There is no mixing of the two memory models in a single process. You cannot mix a GC only framework with a non-GC only framework.

When building a framework, you can set GC to "supported" at which point in time the framework could be used in either a GC'd or a non-GC'd process. However, you will have to maintain correctness for both running environments separately.

What is this "Blocks" framework to which you refer? If you are talking about Blocks, the language feature shipped in Snow Leopard's Objective-C, then it works just fine under both GC and non-GC.

As stated in the garbage collection programming guide, "Code compiled as GC Required is presumed to not use traditional Cocoa retain/release methods and may not be loaded into an application that is not running with garbage collection enabled."

So no, unfortunately. But how much work it would be to adopt garbage collection depends on your app. You might try testing to see if it looks like a big project. (It often is, but sometimes it's not so bad.)

In project settings, you can compile with GC supported (NOT required) and they should mix just fine. Compiling with GC supported but not required should allow retain/release to work alongside GC

So if you wanted your Framework to play nice with anything, you'd be better served to compile with -fobjc-gc instead of -fobjc-gc-only.

Apparently I was having a hard time getting my thoughts to the keyboard yesterday. According to the docs:

-fobjc-gc-only This means that only GC logic is present. Code compiled as GC Required is presumed to not use traditional Cocoa retain/release methods and may not be loaded into an application that is not running with garbage collection enabled.

So if you build your framework with GC Required, you can't load it into a non-GC-enabled application.

Also according to the docs:

-fobjc-gc This means that both GC and retain/release logic is present. Code compiled as GC Supported is presumed to also contain traditional retain/release method logic and can be loaded into any application.

So while the burden is on the developer to include retain/release logic in a project that is compiled GC Supported, this allows a framework to be loaded in any application.

I apologize for my unclear rambling yesterday. I was running on 3 hours sleep and trying to do several things at once. Never a good idea.