Adding compile flags for multiple targets in XCode

I have a app that has multiple targets. Each target has different features. Where and how do I define complier flags so that when I build each target will only have the features that I assign to it.

For instance I like to do something like this.

#ifdef APP1

#define FEATURE_A
#define FEATURE_B

#elif APP2

#define FEATURE_B

#els开发者_如何学运维e

#endif

Where would I put #define APP1 or #define APP2. APP1 and APP2 are the bundle IDs of the apps. I would like to do it so that the definitions are not defined dynamically when the application runs (i.e. should not be in an if statement), but rather set when I build the application.

Any suggestions?

Thanks.

Put corresponding definition in target's settings, 'Preprocessor Macros' section.