XCode 5 - Undefined symbols for architecture armv7: - ios

Question

I am getting this error for a single class from a static library, which I have compiled myself. It has all been working fine and I wanted to add another class as a simple data transfer object called PPClientData.
The error is:
Undefined symbols for architecture armv7:
"_OBJC_CLASS_$_PPClientData", reference from: objc-class-ref in
CPPIntegrationDelegate.o
The relevant file is included in the library compile targets and I have used otool -d on the (fat) library and it shows
libPPIntegration.a(PPClientData.o) (architecture armv7):
(__DATA,--data) section
The header for the class (PPClientData.h), which is included in the app is like this:
#import <Foundation/Foundation.h>
#interface PPClientData : NSObject
#property(nonatomic, strong) NSString* clientId;
// 3 others identical to the above with different names
#end
and the .m file which should be compiled into the library looks like this:
#import "PPClientData.h"
#implementation PPClientData
#synthesize clientId;
//Synthesize others
-(id)init {
self = [super init];
return self;
}
#end
It is consumed in a single class in the app as follows. If this one function that consumes it is commented out, the linker error goes away (it links to other classes in the library) but with this in, it fails. This is a delegate function for the library.
#import "CPPIntegrationDelegate.h"
#import "PPClientData.h"
#implementation CPPIntegrationDelegate
// Various other functions that work fine
-(PPClientData*)clientData:(PPIntegration*)integration {
PPClientData* dict = [[PPClientData alloc]init]; // This is the line that causes the linker error
dict.clientId = #"whatever";
// set other properties of dict
return dict;
}
I understand what the linker is trying to do and what the error suggests but I don't see what I've missed. Can anyone help?

Answer 1

If you are on Xcode 5.1, try to remove arm64 from Valid Architectures (under Build Settings) and also change the Architectures from "Standard architectures" to just armv7 and armv7s. This might be relevant to you: how to stop xcode5.1 building for 64bit

Answer 2

Well, it wasn't the architectures causing the problem but in some way, xcode or whatever had been confused by the order of the forward declaration of the class I was using and then the definition itself. Initially, the broken code was something like:
BrokenClass.h
// Definitions etc.
GoodClass.h
#class BrokenClass;
- (BrokenClass*)someMethod:(SomeType*) param;
GoodClass.m
#import "BrokenClass.h"
- (BrokenClass*)someMethod:(SomeType*) param
{
}
Which was included into my App by including GoodClass.h into a header file, which forward declared BrokenClass and then included BrokenClass.h into an m file which should have completed the definition, where the class was used.
Anyway, to fix it, I changed the GoodClass code to:
GoodClass.h
#import "BrokenClass.h"
- (BrokenClass*)someMethod:(SomeType*) param;
Removed the #import in the m file and then only included the one GoodClass.h into my app (which brought in the BrokenClass).
Whether this is a bug somehow or more likely, I had too many forward declarations etc. I'm not sure.