Undefined symbols for architecture x86_64 on Xcode 6.1
All of a sudden Xcode threw me this error at compilation time:
Undefined symbols for architecture x86_64:
"_OBJC_CLASS_$_Format", referenced from:
objc-class-ref in WOExerciseListViewController.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
After doing some research, I may understand that a library I'm using is not compatible with 64 bit version. But this is very strange since I've been working with the same libraries for at least a week without having a single compilation problem during that time. The two libraries are just composed of a bunch of classes, and when I removed them from my project I got the same issue. Since I have never created libraries myself, I have no idea how I can find wether the ones I'm using are compatible with 64 bit (?) I also tried the following changes for architectures under the target panel :
- added $(ARCHS_STANDARD_INCLUDING_64_BIT) to the Architectures
- build active architecture only -> set to 'NO'
- for 'valid architectures' -> set to arm64, armv7 and armv7s
- deleted the DerivedData folder and its contents, cleaned and built again
But none of these changes work. Please, does someone have a clue on this? Thanks
Answer
Apparently, your class "Format" is involved in the problem. Check your declaration of this class, especially if you did it inside another class you probably forgot the @implementation or something similar.