How to link “.a” fat-static-libs with Apportable?

Question

How do I link ".a" fat-static-libs with Apportable?

In the beginning, I did get a warning,

Warning: Library not found for lib-name. Try adding this to the 'deps' array in the 'add_params' section of your configuration.json file. Check ~/.apportable/SDK/System for the directory names that correspond to 'deps' entries.

I did add it to "deps" in the JSON right where it says this:

// A list of dependencies. Typically these correspond to frameworks in the xcode project.

My library isn't a framework, though. It's just a .a static library that has armv7, armv7s, and i386 parts which I assembled using lipo from two libraries (an armv7 and armv7s .a and a i386 .a) built with Xcode. They both use a single framework which is this Boost framework.

Adding it under deps squelched that warning message, but the apportable linker is still giving undefined references, so it is still not properly linking this file.

Now I know that Apportable has to re-jitter all this stuff, since Android won't know what to do with a Mac-executable format, so it's probably got to go pick apart my library and possibly turn it into an ELF-library before final linking. I'm not sure how to go about debugging this at this point, but is this supported at all?

Answer 1

Since you get "library not found" that means Apportable simply can't find the file. Hence the problem is merely with the file's location (or existence) and not what's in the library or how it is built.

The most common issue with dependent targets, especially Xcode projects dropped into other Xcode projects respectively workspaces with multiple projects, is that the resulting output of each target/project goes to different folders. Then Apportable (as well as xcodebuild under some circumstances) can't find the resulting libraries.

First step you should try is to make sure that the target dependencies are set. Select the app target, go to the Build Phases pane and under Target Dependencies add all frameworks and libraries that appear in the list and that your project depends on. This should ensure that the dependent frameworks/libraries do get built - because Xcode's built-in automatic dependency resolution isn't available to command line tools from what I understand. So you need to explicitly specify the dependent projects respectively their output.

If that doesn't help, you can force all targets to write their output to the same folder. Under Build Settings for every target change the Build Products Path (symbolic name: SYMROOT) to the same folder, for example ~/myprojectsbuildoutput

That way even dependent other projects will place their output in the same folder and xcodebuild as well as Apportable (it depends on xcodebuild) will be able to find the library files.

Tip: make sure your project builds successfully on the command line. Open Terminal, cd into the folder where the .xcodeproj bundle is and enter xcodebuild. If xcodebuild fails merely due to validation, disable Validate Built Product under Build Settings of the app target. If xcodebuild fails, Apportable likely isn't going to work either because it depends on xcodebuild. So as a prerequisite make sure that xcodebuild works on your project.

If xcodebuild also gives you "library not found" try calling it with a specific SYMROOT:

xcodebuild SYMROOT=~/myprojectsbuildoutput

If that then works you know you have to update each target's Build Projects Path. From what I know it's not currently possible (or not documented) to pass custom xcodebuild parameters via Apportable, so it needs to be set up in the .xcodeproj itself.