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

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.

Answer 2

I think I've stumbled on a slightly better approach while trying to integrate the Cocoapods xcconfig files into my own. I like to set the following in my projects

GCC_PREPROCESSOR_DEFINITIONS = CONFIGURATION_$(CONFIGURATION)

Unfortunately this conflicts with the definitions that comes with the Pods.xcconfig. As is stated elsewhere $(inherited) doesn't work as expected. What does work is the following

GCC_PREPROCESSOR_DEFINITIONS[config=*] = CONFIGURATION_$(CONFIGURATION) $(inherited)

UPDATE:

If you need to override a setting for a particular configuration then you'd be tempted to write something like

GCC_PREPROCESSOR_DEFINITIONS[config=*] = CONFIGURATION_$(CONFIGURATION) $(inherited)
GCC_PREPROCESSOR_DEFINITIONS[config=Debug] = DEBUG=1 CONFIGURATION_$(CONFIGURATION) $(inherited)

Sadly this won't work BUT putting the second declaration into a file that only get's loaded by the Debug configuration will properly override setting.