Question

I’m trying to build for multiple targets in Xcode, to simplify the process of creating a ‘lite’ and ‘pro’ version of my application. In theory, this is great and I can pass defines to GCC_PREPROCESSOR_DEFINITIONS for use in my code. However, I’m having problems actually getting it to work due to an error trying to launch the second target in the simulator: Failed to launch simulated application: Unknown error.

Here is the simple process I’m using to create the additional target:

1. Add #ifdef MYAPP_PRO to source files to modify behavior based on pro/lite version of app (and verify application is working as expected)
2. Select Project > New Target... from menu, and pick ‘Cocoa Touch Application’ (named MyAppPro’)
3. Edit new target settings; add GCC_PREPROCESSOR_DEFINITIONS user-defined setting and set the value to ‘MYAPP_PRO’ (no quotes)
4. Set active target to ‘MyAppPro’; build and run.
5. Failed to launch simulated application: Unknown error.
6. Copy all settings from Info.plist to MyAppPro-Info.plist and try again
7. Failed to launch simulated application: Unknown error.

The build completes just fine, but I’m unable to run in simulator.

Editing the project.pbxproj in the .xcodeproj directory, I notice there are some key differences between the two target definitions’ build settings. I tried manually editing the file but must have done something wrong because I couldn’t get it to load in Xcode afterwards.

Original target’s ‘Debug’ build settings:

        buildSettings = {             ALWAYS_SEARCH_USER_PATHS = YES;             ARCHS = '$(ARCHS_STANDARD_32_BIT)';             'CODE_SIGN_IDENTITY[sdk=iphoneos*]' = 'iPhone Developer';             GCC_C_LANGUAGE_STANDARD = c99;             GCC_WARN_ABOUT_RETURN_TYPE = YES;             GCC_WARN_UNUSED_VARIABLE = YES;             ONLY_ACTIVE_ARCH = YES;             PREBINDING = NO;             SDKROOT = iphoneos2.2.1;         }; 

Thew new MyAppPro target’s ‘Debug’ build settings:

        buildSettings = {             ALWAYS_SEARCH_USER_PATHS = NO;             CODE_SIGN_IDENTITY = 'iPhone Developer';             COPY_PHASE_STRIP = NO;             GCC_DYNAMIC_NO_PIC = NO;             GCC_OPTIMIZATION_LEVEL = 0;             GCC_PRECOMPILE_PREFIX_HEADER = YES;             GCC_PREFIX_HEADER = '$(SYSTEM_LIBRARY_DIR)/Frameworks/UIKit.framework/Headers/UIKit.h';             INFOPLIST_FILE = 'MyAppPro-Info.plist';             INSTALL_PATH = '$(HOME)/Applications';             OTHER_LDFLAGS = (                 '-framework',                 Foundation,                 '-framework',                 UIKit,             );             PREBINDING = NO;             PRODUCT_NAME = MyAppPro;             SDKROOT = iphoneos2.2.1;         }; 

Answer 1

You didn’t say whether you actually ever added source files to the target. A new target (unlike a new project) has no source file templates; you have to add them yourself. So the Simulator might be telling you ‘you built successfully, but there’s nothing to run.’