Building a C static library using recent Xcode? Including that in Swift? - xcode

Does anyone have a guide to setting up a project that produces a static library under recent versions of Xcode? There are a few for older versions, but they use a project setting called "C/C++ Library" which seems to have been removed.
I notice "External build system" is still in there, and maybe that's a solution? The C code won't be changing structure too much, so a makefile could be a solution - but I've never used this type before, so I'd like to hear from people that have.
Ultimately the C code will be consumed by a Swift/Cocoa application. Am I correct in thinking that I simply include both projects in a workspace, drag the .a and bridging .h into the Swift project, and go?

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How to compile swift library project into .so file?

I'm new to XCode and Objective C / Swift. I'm trying to make a Swift library project that doesn't depend on cocoa or anything. So it's just Swift files. What type of project should I be creating (I'm assuming there are multiple ways of doing this? How do I need to configure the project so that it builds to a .so file? And finally, how do I build it to a .so file?
I'm using Xcode6-beta.
You can create a Swift library for iOS by creating a new Xcode Project and selecting iOS/OS X -> Framework & Library -> Cocoa Touch Framework and then setting the language to Swift on the next screen.
Once this project has been created you are not required to link against the Cocoa frameworks, and can remove any references to them if needed.
Upon compiling this project Xcode will create a .framework folder in your build directory which contains a dynamic library which you should then be able to link against. Note however that I haven't had any success myself yet at linking directly against this file, even though it appears to be a standard dynamic library.
In terms of using this shared object file on Android I believe you will be out of luck, as the Swift language (much like Objective-C) requires a runtime library which is simply not available on other platforms at this time.
... I think you are limiting your train of thought a bit or expecting leaps and bounds to quickly swift is ready to work with objective c and cocoa so you aren't going to be able completely avoid cocoa however you wont have to write any of it the compiler will do that for you. but you will still have to use cocoa frameworks or modules like foundation( contains many specialized objects for program development), UIKit, CoreData however these don't require you to write the cocoa. and if Im not mistaken the .so file is made on compile so you never actually touch that file but rather is supporting files .swift
to do it
if your looking to do everything programmatically or if you want to xib or storyboards just make a new project I prefer an empty project.(set programming language to swift and decide if you want core data or not finish the project wizard thing and bam you have a YourAppDelegate.swift you can make another .swift file or a storyboard and hopefully you know what to do from there. Swift book is available on ibooks for free its nicely written
although it will be quite a while before cocoa and swift are completely separate... if ever

How to organize C source file previously compiled by GCC Make and build them into an Xcode bundle? I have a Duplicate Symbol _main Error

How to build a .bundle from source code?
This might sound like a simple problem but it has been hurdling me for a week...
Here is my problem:
I have a bunch of .c and .h files that are organized in a folder and its sub folders. The source code was written and compiled with gcc make and tested by many other make tools. The source code has some utilities and command line tools and it has more code that serve as library for those utilities and tools. It is the files that serve as libraries that I want to reuse. (By library I don't mean static library or something, I just mean that some .c and .h files in certain subfolders provide functions that can be called by some other .c files. I want to be able to call those functions, too)
Yet my problem is more complex than that: I need to build those .c and .h into a bundle to reuse it. I am not writing my application in C; I am developing in Unity and Unity can only take in .bundle files on Mac OS.
Here is my goal:
Organize the source code folder in a proper way so that I can build them into a bundle in Xcode 4.
Here is where I got stuck:
When building the project I got the following error:
Duplicate symbol _main in
/Users/zeningqu/Library/Developer/Xcode/DerivedData/ccn-cfygrtkrshubpofnfxalwimtyniq/Build/Intermediates/ccn.build/Debug/ccn.build/Objects-normal/i386/ccndsmoketest.o
and
/Users/zeningqu/Library/Developer/Xcode/DerivedData/ccn-cfygrtkrshubpofnfxalwimtyniq/Build/Intermediates/ccn.build/Debug/ccn.build/Objects-normal/i386/ccnd_main.o
for architecture i386
I can relate to this error because I can find lots of main entries in the source code. Most of them are test utilities.
Here is what I tried:
I tried removing all those utility .c files but with no luck. The error is still there. I delete and delete until some files cannot find the definition of the function they are calling. So I had to stop there.
Though I wasn't able to build a bundle I was able to build a C/C++ static library (with an .a extension). After I got the .a file I tried to put it into another Xcode project and tried to build it into a bundle. I could build a bundle in that way, but then I had problem accessing the content of the bundle. How do I call functions defined in a .a static library if that library is hidden in a bundle? I read about Apple's documentation which says:
Note: Some Xcode targets (such as shell tools and static libraries) do
not result in the creation of a bundle or package. This is normal and
there is no need to create bundles specifically for these target
types. The resulting binaries generated for those targets are intended
to be used as is.
(quoted from: https://developer.apple.com/library/mac/#documentation/CoreFoundation/Conceptual/CFBundles/AboutBundles/AboutBundles.html#//apple_ref/doc/uid/10000123i-CH100-SW1)
Here is what I thought about:
I thought about replacing all main with something like main_sth. But the source code was not written by me so I didn't want to modify it. (It just doesn't feel like a proper way of doing things to me...)
I learnt that Xcode has gcc compiler built in. So I guess if gcc can make it, so can Xcode? It's just a wild guess - I am not familiar with Xcode and gcc.
Here is a summary of my questions:
Is there a way to properly organize a pile of code previously compiled and made by gcc make so that they can be built into an Xcode bundle?
Is it meaningful to put a .a library in an Xcode project and build it into a bundle? If it is meaningful, how do I call functions defined in .a after it is built into a bundle?
Is it proper to just replace all main() entries with something else?
Alright I think I have figured out at least one solution to the problem.
The duplicate main error was caused by a bunch of main entries in my source code. When the code was compiled by gcc make, I guess the author defined a sort of compilation order so that duplicate mains won't be an issue. (If you know how to do this, please let me know. I barely know make tools.) But when I just add the entire source code folder into my Xcode project, of course Xcode would complain during linking...
As I was unwilling to modify the source code (because the source code library is not developed by me), I decided to use another strategy to walk around this problem.
If your duplicate main error was reported from your own code, you can stop reading here. But if you are like me, with a bunch of gcc compiled source code and badly need a bundle yet don't know what to do, I may be able to help.
Okay here is what I did:
I set up an empty workspace.
I built a C/C++ static library project.
Import my entire source code folder into the static library project.
Set some header search path for the static library project.
Build the static library project. (Now I have a .a library which I could link against)
I set up another project, with a bundle target.
At the bundle project -> Build Phases -> Link Binary with Libraries, add the .a library that I just built.
At the bundle project -> edit scheme -> Build, add the static library project to the scheme and move it up the list so that it is built prior to my bundle project.
Then add .h files of my library project to my bundle project as references.
After that, add a .c file in my bundle project that basically functions as a wrapper. I picked a function that I want to call in Unity, wrote a wrapper function in the new .c file, and was able to build the bundle.
After several trial and error, I was able to import the bundle into Unity and was able to call the test function from Unity.
I was really excited about this! Though it's not completed yet I think this gives me hope and I am confident I can use the source code now! And the best thing about this solution is that I don't have to modify the library code developed by others. Whenever they update their code, I just update my .a library and that's it!
Though I have listed 11 steps I still feel that there are lots of details that I missed. So here are my references:
I followed this tutorial to build my source code into a static library: http://www.ccnx.org/?post_type=incsub_wiki&p=1315
I followed this blog to link static library against my bundle code and twist build phases and search headers: http://blog.carbonfive.com/2011/04/04/using-open-source-static-libraries-in-xcode-4/
I followed this doc to import my bundle to Unity3D Pro as a plugin: http://unity3d.com/support/documentation/Manual/Plugins.html
I strongly recommend the second reference because that's what solved my problem!
Though the problem is almost solved there are still a few things that I haven't figured out:
I don't know if a wrapper function is at all necessary. I will try this out tomorrow and come back to update.
-- I am coming back to update: the wrapper function is NOT necessary. Just make sure you have all the headers in your bundle project and you will be able to use all the data structures and call functions defined in your headers.
I haven't used NSBundle class though I read a few docs about it. Previously I was thinking about using that class to access my .a library encapsulated in my bundle, but as I found the solution I wrote above, I didn't try the class out.
Lastly, if you have better solution, please don't hesitate to let me know!
I tried to follow the steps in the accepted answer, but had no luck. In the end, I realised step 10 needed to be modified slightly:
Create a dummy.c under (.bundle) project and the dummy.c can just be totally empty.
Remove the setting for the library you want to link inside Link Binary With Libraries
Instead use -Wl,-force_load,$(CONFIGURATION_BUILD_DIR)/libYourLib.a or -all_load to Other Linker Flags
PS: And also can use sub-project instead of workspace. and use Target Dependencies instead of Edit Scheme to achieve the same effect.

Frameworks are missing in Unity generated Xcode project

Some of the frameworks are missing when I generate Xcode project through Unity. What would be the reason? How can I solve this?
I mean manually I have added them in Build Phases to fix the error, but why are they missing?
They're missing because they are required when you use those APIs.
If you're coming from a language like Java this might seem strange, but with Objective-C (which is ultimately C) you need to let the compiler know where the APIs come from beyond just the header file import.
Unfortunately, Unity doesn't provide any support for specifying additional frameworks for your Xcode project to link to. However, if you can you should generate and modify your Xcode project once and then subsequently always have Unity update rather than override the project.

Creating a library (.a) in Mac OS X and Xcode

I'm in the process of porting some code from Linux to Mac OS X. The code is a static library that you add to your code. Basically after you compile the code you get a MyLib.a that can be linked to whatever project you want.
I'm managing the "project" via a Makefile.
Is there a way to have a project on Xcode that ultimately produces the same kind of library? How?
Thank you for the help.
Sure. You don't say so, but I am assuming you are using C or C++ as source.
Assuming you are using Xcode 3.2.2, you can create a new project (File > New Project...), which will bring up a New Project window with available project templates. Select the "Framework & Library" category under Mac OSX from the list on the left. You should now see a "BSD C Library" and "STL C++ Library" among the other library and framework types. For building a static library like you described you want the "BSD C Library" option. There are static and dynamic options for this which you will see when you click on the icon, but static is default.
Depending on which version of Xcode you are using, the location of the project template may be a little different since Apple has been changing this UI for the New Project window fairly frequently. So if you are not using 3.2.2 you may need to poke around the available projects a little bit.
Oh, and don't worry if you are trying to build C++. Event though this says it is for C, C++ libs build just fine as well.

Setting up a large Xcode project

I have a large exiting C++ project involving:
4 applications
50+ libraries
20+ third party libraries
It all builds fine on Windows using VS8, Linux using QMake (project uses Qt a lot). I also build it on OS X using QMake but I was wanting to setup an Xcode project to handle it in an IDE. I'm struggling to setup proper configuration to easily define dependencies, both to internal libraries and to the third party. I can do property sheets and .pri files in my (disturbed) sleep, but would appreciate some advice on building such large projects in Xcode.
I've been experiencing with Xcode configuration files and #including one from another but it does not seem to work as I would expect, especially when defining standard locations for header files etc.
Is there some good book describing the process of setting up Xcode (remember it's C++, I'm not wanting to learn ObjC at this time)?
Or maybe a good open source project I could learn from?
Thanks!
Step in to Xcode may be the book you're looking for. It's got a whole section devoted to using AppleScript to automate configuration includes. I've been going through the book myself on O'Reilly Safari as I've found myself in a situation similar to yourself!

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