xcode - How to append values in xcconfig variables?

Question

I'm using Xcode and .xcconfig files. I'm trying to append some values in the preprocessor definitions, but I simply can't make it work.

I tried the following (as well as many variations of this), but no luck so far:

GCC_PREPROCESSOR_DEFINITIONS = '$(GCC_PREPROCESSOR_DEFINITIONS) NEW_VALUE'

The NEW_VALUE symbol is simply never added to the preprocessor definitions.

Does anyone had success appending new values to variables in xcconfig files?

Answer 1

For reasons stated in other answers to this question, you can't inherit values easily.

I recommend defining your settings in cascade. Let's assume APP is your project prefix and make this simple defining only a few CFLAGS:

platform.xcconfig:

APP_PLATFORM_CFLAGS = -DMAS=1

project.xcconfig:

#include "platform.xcconfig"
APP_PROJECT_CFLAGS = -DBETA=1

target-one.xcconfig:

#include "project.xcconfig"
APP_TARGET_CFLAGS = -DSUPER_COOL=1
#include "merge.xcconfig"

target-two.xcconfig:

#include "project.xcconfig"
APP_TARGET_CFLAGS = -DULTRA_COOL=1
#include "merge.xcconfig"

merge.xcconfig:

OTHER_CFLAGS = $(inherited) $(APP_PLATFORM_CFLAGS) $(APP_PROJECT_CFLAGS) $(APP_TARGET_CFLAGS)

Then, you'll base each of your targets build configurations on target-xxx.xcconfig. A real project will use more complex setups, using a configuration file for the project and a different one for the target, but you get the idea.

Also, remember that $(inherited) refers to higher level in the hierarchy, not earlier. For instance, it inherits from Project level at Target level. Not sure if this apply to Xcode 4 too.

This is a simplification of GTM, go there to learn more.