Question

I am trying to do weak linking to NSSystemClockDidChangeNotification constant. As per the apple docs I wrote

extern NSString * const NSSystemClockDidChangeNotification __attribute__((weak_import));

I got an error,

“_NSSystemClockDidChangeNotification”, referenced from:

_NSSystemClockDidChangeNotification$non_lazy_ptr in DateTimeChange_NotifAppDelegate.o
(maybe you meant: _NSSystemClockDidChangeNotification$non_lazy_ptr)

ld: symbol(s) not found

collect2: ld returned 1 exit status

How to resolve this?

Answer 1

“_NSSystemClockDidChangeNotification”, referenced from:

means that NSSystemClockDidChangeNotification constant does not present in the basesdk your are using.what is the basesdk you are using?
just check it and I feel this constant presents in 10.6 and later