I'm getting this error
Undefined symbols:
".objc_class_name_MyClass", referenced from:
literal-pointer#__OBJC#__cls_refs#MyClass in infoViewController.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
When referencing the static method below:
[MyClass ClickComment:self.navigationController];
MyClass is defined in a static library that I'm referencing in my app project. When I start typing "[MyClass "..., I get message hints. The app project knows MyClass exist and which methods are defined on it. Yet, I get the above error. Commenting out this call allows the project to build without error.
In the static library, I have a .h file that references all of the library's .h files. This way, the app project needs to reference only one .h file from the static library. The static library project also has an app. I use it to test the static library. I can do the above call fine. I usually see these types of errors when the static library has build a device/debug version and the app project has build simulator/debug. However, both builds are in sync.
I know there is a reference issue but I'm unsure how to resolve it. Any suggestions?
That means that the header files are found during compilation, but the linker is not aware of the static library. Make sure your static library is listed under "Targets -> YourMainTarget > Link Binary with Libraries" in the project view.
See http://developer.apple.com/tools/XCode/XCodeprojects.html
Related
I seem to get this strange issue when testing an XCTestCase. I created a unit testing bundle, and set my main app as the "target"; now I can write tests against my Core Data NSManagedObjects just fine, but if I include anything else in my app that isn't an NSManagedObject, I get linking errors:
Undefined symbols for architecture x86_64:
"_OBJC_CLASS_$_iCloudListener", referenced from:
objc-class-ref in SLTestToDoWithRepeatInterval.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
This only happens with non-NSManagedObjects. And iCloudListener is definitely in the Compiled Sources for the main app target. The problem is that though I can go and add this particular iCloudListener class into the test target -> Build Phases -> Compile Sources list, and that will make this particular linking error go away, but it introduces new ones since it starts giving linking errors about all the header files from the iCLoudListener class; and if I start adding those, they require more and more files, to the point where I have to include pretty much all of my code into the test target "Compile Sources" section.
Is there something I'm doing wrong here? Is there a setting which might be causing Xcode to ignore the non-NSManagedObject classes?
It's because the project inserted the core data's xcdatamodeld file in compile sources. Select your project -> Build Phases -> Compile Sources and delete projectName.xcdatamodeld file.
And also check if you have imported .m file instead of .h file, it also gives the same linker error.
Check all the #import codes.
And check if you have added core data frame work in library and imported core data .h file. Check for creation of NSManagedObject and import it's file.
Just try it and reply me if still any error.
I've workspace with two project: static lib and cocoa application. Static library link some system frameworks(libcrypto.dylib) and include dynamic lib's .h files(openssl/bn.h openssl/rsa.h). My static library compiles successfully.
Cocoa application uses this static library and at compile time gives an error: "undefined symbols, symbols not found" (bn, new rsa etc).
But when I include libcrypto.dylib also into cocoa application project then there is no error.
Question: Xcode can do this automatically, by taking dependency from the static link library?
Thanks.
The answer is unfortunately no. It is common practice to include each single static library in the project that requires the code. That is just the way it is done.
There is an interesting article on how to handle multiple static libraries in an XCode project.
I've build a Framework for an Objective-C App. I've tested it on minimalistic Programs where it worked. I was trying to use it in a real App now. Unfortunately the linker can't find the definition of my classes. =(
When I try to run it, I get the following Error Message:
Undefined symbols for architecture x86_64:
"_OBJC_CLASS_$_ClassInMyFramework", referenced from:
objc-class-ref in libMyLib.a(MyLib.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
The Dependency:
App -> libMyLib.a -> MyFramework.framework
The usual suggestion for this error message is to add the framework into the "Link Binary with Library" Build Phase... I can assure you that this has happened ;)
My first thought is that something might be wrong with the Build Settings which results in this linking error.
On second thought It may have to do with the Project-Setup. Is it possible to statically link a framework into an '.a' library file?
Update:
I've linked the Framework into the App and now it's working. But I don't consider this a clean solution. Help still appriciated. =)
The short answer is no, you can't link the framework statically into your .a file. See this discussion.
The reason is, the static library doesn't include the object code (the definition) of classes from the dynamic framework. The static library links to object code in the framework the same way the app links to the framework code: at run-time.
From Apple's Framework Programming Guide: "Dynamic shared libraries have characteristics that set them apart from static linked shared libraries. For static linked shared libraries, the symbols in the library are checked at link time to make sure they exist. If they don’t exist, link errors occur. With dynamic shared libraries, the binding of undefined symbols is delayed until the execution of the program."
It depends on what you want to be able to do with your code. You could add a static "target" for your framework project, so your framework project outputs both a framework and a static library. You could include this static library into apps.
But, one benefit of frameworks is that you can include nibs, images, headers, etc. So, linking your framework into your apps directly is not a bad way to go. Otherwise, you need to include these assets directly into your project. If you want this framework to be distributed with your app, you'll need to package it inside the app wrapper.
It looks like some people create a "static framework" for inclusion into an iOS project, but this looks a bit hacky to me.
As an interesting exercise, you can explore the symbols in your object code. Let's say you are using a ClassInMyFramework (from your framework) somewhere in your static library, like:
ClassInMyFramework *myFramework = [[ClassInMyFramework alloc] init];
The static library will then include the _OBJC_CLASS_$_ClassInMyFramework symbol. You can see the list of symbols in your static library file at the command line:
$ nm /path/to/libMyLib.a
This will output a list of symbols, which will show that _OBJC_CLASS_$_ClassInMyFramework is undefined (note, the "U" designates that the class is undefined):
U _OBJC_CLASS_$_ClassInMyFramework
Whereas, if you were do to the nm command on your framework:
$ nm /path/to/MyFramework.framework/Versions/A/MyFramework
Your output would show that the symbol is defined in your framework (though the definition will still only linked at run-time), which would look something like this, showing an address of the definition:
0000000000001100 S _OBJC_CLASS_$_ClassInMyFramework
When trying to use the SmartfoxServer-framework inside a Kobold2d project we are getting the following error:
Undefined symbols for architecture i386:
"_OBJC_CLASS_$_CCAsyncObject", referenced from:
objc-class-ref in libcocos2d-extensions-ios.a(CCTextureCache+CCBigImageExtensions.o)
ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1
This happends due to the fact, that we have to include the -ObjC linker flag to have the categories loaded, which are defined in the SmartfoxServer-framework. I already read about the need to force-link a static library which contains categories here, but the SmartFoxServer-Framework isn't a static library.
Is there a way to force load a framework, so it includes all the categories without using the -ObjC linker flag? Or is there a convenient way to convert a framework to a static library? Any help is greatly appreciated!
Unless you are using CCBigImage, you can deselect the CCTextureCache+CCBigImageExtensions.h and .m files from the target.
Open the Kobold2D-Libraries project and browse to the group /Extensions/CCBigImage. From the menu choose View -> Utilities -> File Inspector. Select each file and uncheck the target checkbox in File Inspector. Now this particular class won't be compiled anymore and the error is gone.
The problem seems to be that this category uses a private class that's defined only in the implementation file. Unfortunately force loading the entire cocos2d-iphone-extensions project is not a solution because this brings up other errors.
I have a class called PrimeNumber that I wrote recently, which worked absolutely fine with a Foundation Tool and a Mac application. However, trying to use it with an iPhone application fails. I added the .m and the .h files to my project and imported the .h file to my ViewController.h like this:
#import "PrimeNumber.h"
After trying to use a method declared in my PrimeNumber class and run my application, Xcode showed me two errors:
Undefined symbols for architecture i386:
"_OBJC_CLASS_$_PrimeNumber", referenced from:
objc-class-ref in ViewController.o
ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)
The PrimeNumber.h and PrimeNumber.m files are not red in the Project navigator. Product > Clean doesn't work either. Also, because my classes aren't declared in a framework, I do not think something like that can be the problem.
Can anyone tell me what I'm doing wrong? Thanks!
Edit: changing the class name to PrimeNumbers, then creating a new Objective-C class called PrimeNumber and copy-and-pasting the complete contents of .h and .m files of the PrimeNumbers class into the .h and .m files of the PrimeNumber class worked for me. Weird, but it worked. :)
You have to add it to the "Compile Sources" Build Phase as well.
Project -> Targets -> [Your Target] -> Build Phases -> Compile Sources (just drag PrimeNumber.m in there)