When using Three20, suggesting no: TTCreateNonRetainingArray ()

My code is:
- (Id) init {

if (! (self = [super init])) {
/ / Initialize member
locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;
locationManager.desiredAccuracy = kCLLocationAccuracyBest;
locationManager.distanceFilter = 10.0f; / / in meters

/ / Create array of delegates
_delegates = TTCreateNonRetainingArray (); / / is here! ! ! !

statusLocation = LocationInit;
self.currentLocation = nil;
}
return self;
}


Link error is:
Undefined symbols:
"TTCreateNonRetainingArray ()", referenced from:
- [Xxxxx init] in xxxxx.o
ld: symbol (s) not found
collect2: ld returned 1 exit status

Tip of the link error, indicating that the header file contains, I checked, TTCreateNonRetainingArray () function header file:
TTGlobalCore.h inCorresponding library are: libThree20Core.a. I linked library, added to Fromeworks in. Where else missed it?
Reply:
There is not configured three textbooks Well, take a good look.
There are a lot of things to set up, I do not know where the problem you
Reply:
This problem usually check from several aspects:
A header file
(2) Other Linker Flags see you need to write the name of the static library does not have, such as: lXXX
3 Look Library Search Path option, if the library file path plus
Reply:
You use the nm command to determine whether the library contains TTCreateNonRetainingArray libThree20Core.a method.