Declaring extern NSString causes linker error

Question

This is ridiculous, im trying to create a sound bool to turn of in app sounds. I keep getting

Undefined symbols for architecture i386:
\"_kPlaySoundPrefsKey\",         


        

Answer 1

First, ensure it is defined:

// AppDelegate.h
extern NSString* const kPlaySoundPrefsKey; // << declaration

// AppDelegate.m
NSString * const kPlaySoundPrefsKey = @"kPlaySoundPrefsKey";  // << definition

see also:

"extern const" vs "extern" only

3 questions about extern used in an Objective-C project

Linker error using extern "C" in Objective-C code