Question

I have seen some libraries use separate branches in their source control. One for ARC one for non-ARC. I dont see this as partical as it requires extra maintaince.

A method I thought was to use the compiler flag: (see this question)

#if __has_feature(objc_arc)   

Whenever I need to use retain release etc… That way if the user has it switched on the code will automatically re-factor itself.

• Is there a disadvantage of doing this way?

• Is there a better way to do it?

Answer 1

While Dave’s answer is correct, there is an alternative pattern that avoids having to maintain two memory models in your code.

Namely, compile your code with ARC required and either:

• use a static library to distrubute your code; whether that static library is built by a new target in the destination project or you distribute the library itself, ARC can be turned on for the target that builds the library.

• turn on ARC for just the files when added to whatever target in the target project. ARC can be turned on per-file.

In any case, mixing ARC and non-ARC code at the per-file level is fully supported and works just fine (as demonstrated by the fact that the system frameworks are almost entirely compiled non-ARC, but work fine from ARC).