Multiple Targets in Xcode: "Failed to launch simulated application: Unknown error."

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."

Answer 2

How did you managed to get this working exactly? Thanks.