I have a library that has both debug build and release build, how do I let Xcode link to the corresponding library base on the current configuration (debug/release)?
I have the same problem except with frameworks instead of static libraries. Having different framework search paths for different configuration and doing -framework YourFramework.framework for both configurations should work but seems not so clean. (or same approach with static libraries)
Related
I am developing a static library, which is added to my main project that tests the static library's functions. The static library inside is using some 3rd party components, and this third party components needs to add some additional libraries (e.g.: libz.dylib, SystemConfiguration.Framework). It's fine, but when I try to build my main project that contains my static library, I got bunch of linker errors. I figured out, if I add the same frameworks and libraries to the main projects what I needed to add to my static library, the linker errors disappear and the project is built succesfully. The question is do I really need to add all of those resources to the main Project? I find it crazy that if I give my static library to someone else to use, I need to include a bunch of frameworks and libraries in the documentation that has to be added also in the integrator project? Or am I missing something important?
It's because a static library is not linked, unlike an executable or dynamic library.
A static library is just an archive of object files, and object files contain external references to symbols they use. Those references are not resolved until the executable/dynamic library is linked.
Therefore when you link-in a static library you are responsible for providing any dependant libraries to the linker, which can themselves be either static or dynamic.
I'm trying to write a simple game engine for iOS in Objective C and C++ using Xcode.
I've made a game project and a game engine project. The latter is added to the former as a subproject. The engine is also added as a target dependency and as a binary to be linked in the game project.
My engine uses CADisplayLink so I add QuartzCore.framework in the engine project's "Link binary with libraries list" (found in Build phases).
Now, when I try to build my game project (the project with the subproject), I get this error:
Undefined symbols for architecture i386: "_OBJC_CLASS_$_CADisplayLink", referenced from: objc-class-ref in libVoya-iOS.a
This error only happens when building from the game project - doing it from the engine project works fine. If I add QuartzCore.framework to the game project building works fine.
Can it really be true I have to specifically require frameworks that one of my target dependencies already have required? In this case: My engine (sub project) already links QuartzCore - is it really necessary to also do this in the projects using this engine? It feels like double work for no reason.
Or perhaps I've just completely misunderstood something? :)
Add QuartzCore framework to fix this issue.
I've now found the answer to my question and I'd like to share it.
Static libraries are nothing more than a grouping of the compiled versions of the library's source files. They do not include any libraries they themselves might depend on.
Fusing all dependencies together happens only when you build the actual executable in the very end. For this reason, your application should indeed link against your dependencies' dependencies.
As for the example in my question, that means that my game should link QuartzCore while my game engine should not (even though it is my GameEngine who is using it).
Learn more here:
Duplicate symbol: Include static lib A in static lib B, also include lib A and B in XCode Project
Linking static libraries, that share another static library
I believe this is because you're using a target dependency instead of linking against a precompiled library.
With the use of a mild hack, it is possible to make static frameworks for iOS. Static frameworks are quite convenient to use: they can simply be dropped into new projects without extra steps (like adding them to the build and adding header search paths).
I've recently started doing OS X programming, and the first thing I noticed was that static frameworks don't seem to be available. Dynamic frameworks are obviously available and recommended, but as I want to make a little private framework intended for application use (not installation in /Library/Frameworks), using a dynamic framework in new application projects still requires a bunch of extra steps.
In my ideal world, I'd create a static framework (a framework which contains header files and a compiled .a file), drag & drop the framework onto a new project, and start coding. Is there any way to make such a static framework on OS X?
P.S. I already tried setting the Mach-O output type to "static library" in a normal framework project, but I just get the error Framework target has invalid MACH_O_TYPE value of 'staticlib'..
You can create a dynamic framework on Mac OS X. In your dynamic framework you can set the LD_DYLIB_INSTALL_NAME as #rpath/Foo.framework/Versions/A/Foo
If you have an app that wants to link with this framework then you make sure you run the
install_name_tool -add_rpath <rpath> <full-path-to-app-binary>
So if I had Foo.app
install_name_tool -add_rpath Foo.app/Contents/Library Foo.app/Contents/MacOS/Foo
Now if you just copy your Foo.framework into Contents/Library it should get loaded and everything should work.
I hope this helps.
Probably simpler would be to use a static library with public headers. When you build the static lib you can have Xcode copy the headers for you automatically. And in your target you can add the folder to your search path.
If you use a static library Xcode will strip away some dead code that your app doesn't really need but is compiled into the static lib.
Static frameworks aren't really supported on OS X. They're fairly brittle anyway, and solve a specific problem that exists on iOS but not on OS X.
If you're looking to make it easy for developers to use a library you create, you have a couple options:
Use Cocoapods. They have a tutorial for publishing your library on CocoaPods. This is probably the easiest way to distribute a library on OS X.
Package your library as a framework. If you set the install name correctly (to #rpath/<library name>), the downstream developer merely needs to copy the framework into their Xcode project and set the runtime search path of their application to #executable_path/../Frameworks).
I have a working application which relies on several static libraries, which I've added as dependencies to the application and added to the link with static libraries bit in build phases. Everything builds and runs fine in the simulator and on my attached iPad.
I wanted to create an .ipa for use with test flight so I followed the instructions on test flight's site (http://support.testflightapp.com/kb/tutorials/how-to-create-an-ipa-xcode-4) and some other tutorials relating to creating an archive with an app that uses static libraries (http://diaryofacodemonkey.ruprect.com/2011/03/18/ad-hoc-app-distribution-with-xcode-4/, http://www.musicalgeometry.com/?p=1237).
Following these tutorials, when I create an archive I get linker errors about not being able to find various libraries, for example:
ld: library not found for -lOAuthTouch
(I've also tried using a new project and a new static library project to make sure it's not some setting I've changed and I get the same problem).
This seems to be because I added a build configuration called "Ad Hoc" to my app for creating an archive, and based on the linker command and the fact that adding an "Ad Hoc" configuration to all the static libraries I use allows the archive to be created I'm assuming that the static libraries are being built to a different directory.
I'd rather not have to add a new build configuration to all the libraries I use, so my question is, what should I do to create an archive of my app without tinkering with every library I use?
A second related question: all the tutorials I mentioned say to set the "Skip install" build setting to yes for static libraries, but the Apple documentation (http://developer.apple.com/library/mac/#documentation/ToolsLanguages/Conceptual/Xcode4UserGuide/DistApps/DistApps.html) seems to indicate setting it for the application, rather than the libraries. Anyone know which is right?
It will work, you must simply get the paths correct and make sure you have set Skip install to NO on each of the static libraries in the workspace. I recently went through this and ended up deleting the existing Ad hoc distribution configuration from both my main target and each of the static library targets. The I created a new ad hoc configuration on the main project and each static library project and verified all of the settings in each of them.
See this link, this, and this all of which helped with sort through this.
There are appear to be methods of creating a fat static library ala "http://stackoverflow.com/questions/3520977/build-fat-static-library-device-simulator-using-xcode-and-sdk-4". Is this recommended? Any special steps (i.e., disabling thumb)
Also, if I do use the fat static library, will monotouch/xcode clear out any unused code in the final product?
You definitely need to turn Thumb code off so you can link properly against the library. As far as creating the fat static library goes, I can only say that anecdotally I've done this for a few third-party libraries that I've used and haven't run into issues.
I assume you already know that you need to create the bindings necessary to make calls to the objective-c library from your MonoTouch code and add extra gcc flags in the project properties to link in the static lib. If not, you can get that information on how to do that from the MonoTouch website.