Changing values based on compile settings

Is there a way to create an if statement based on compile settings? I have an App that accesses a web-based API and when compiling in debug mode I want it to use the private beta version but wh开发者_如何学Cen I compile for release I want it to use the public live version of the API.

At the moment I just have a NSString holding the url address.

---

Typically for this sort of thing you would use a preprocessor directive:

#ifdef DEBUG_MODE
    // connect to beta version
#else
    // connect to live version
#endif

You can either define your own DEBUG_MODE symbol, or you can use an existing one (I'm not sure what it might be called for the iPhone SDK).

---

To extend on Greg's answer, you can pass the compiler flag -DDEBUG_MODE (or -D[any name here]) to define DEBUG_MODE and cause the first branch of the #ifdef to be compiled.