Undefined symbols for architecture arm64

Question

I am getting a Apple Mach-O Linker Error everytime I import a file from CocoaPods.

Undefined symbols for architecture arm64:
  \"_OBJC_CLASS_$_FBSession\", r         


        

Answer 1

in some case, if you define one more interface in a .h file, but did not implementation all these interface, this error occurred.

The linker can't found the implementation in .m file, so you need to implementation it in your .m file for every interface.

To resolve this error:

1.in .m file, supply the implementation for each interface. 2.rebuild