How can you check if a constant is set at runtime? For instance, in iOS 4, UIApplicationDidEnterBackgroundNotification is available, but when running on iOS 3 it will through an error if you try to use it.
+1
A:
You should probably look at this other question, which in my opinion also answers yours. if (&UIApplicationWillEnterForegroundNotification != NULL) should be dynamic-linking-safe and tell you whether the constant exists or not.
Romain
2010-07-03 17:08:08
If you are using LLVM, you have to do some tricks to get it to not optomize out your if statement. This works for me.BOOL backgroundOK = if (backgroundOK) { [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationDidEnterBackground:) name:UIApplicationDidEnterBackgroundNotification bject:nil];}
David Beck
2010-07-05 15:04:05