So you're implementing a new notification and you want the name to be a constant. Easy, right?

const NSString* VTMyNewNotification;

If that's how you do constants, you're not doing it quite right. Try assign a new value to the alleged constant and watch in horror as the compiler doesn't stop you.

This is because when you type const NSString*, the compiler interprets that as a pointer to a constant NSString. NSString is already an immutable object, so making a constant NSString doesn't do anything except maybe cause some compiler errors/warnings later when you try to use it. What you're really after is a constant pointer to an NSString. It's ever so subtly different, and written like so:

NSString* const VTMyNewNotification;

Don't feel bad. It's a common mistake. I used to do it until Rob Napier schooled me, and now I'm passin' on the learnin' to you.