Weak linking on iPhone refuses to work

Question

I\'ve got an iPhone app that\'s mainly targetting 3.0, but which takes advantage of newer APIs when they\'re available. Code goes something like this:

if (UI         


        

Answer 1

Aaand I figured it out. For symbols that are not functions (extern const int foobar, for instance), you have to compare against the address of the symbol, not the symbol itself, so:

if (&UIApplicationWillEnterForegroundNotification != NULL)
    etc;

Which in retrospect is kind of obvious, but I still fault the entire universe around me for not ever mentioning the distinction.