How do I know whether the compiler has ARC support enabled?

Question

I need to write a lib in my iOS app.

The statement should be pre-process define as :

myObject ...

#if ARC
   // do nothing
#else
   [myObject releas         


        

Answer 1

You generally do not want to do things like this:

#if ARC
   // do nothing
#else
   [myObject release]
#endif

Because it’s a recipe for disaster, there are many subtle bugs lurking in such code. But if you do have a sane use case for that, you would perhaps be better off with a macro (I didn’t know __has_feature, thanks Justin!):

#if __has_feature(objc_arc)
    #define MY_RELEASE(x) while (0) {}
#else
    #define MY_RELEASE(x) [x release]
#endif

But I would be quite nervous to use even this, the pain potential is huge :)