objective c - Use CLLocationManager and MKReverseGeocoder to get name of city -

i trying name of city of user's current location using mkreversegeocoder has errors cannot recognize. here details:

it has errors cannot recognize

undefined symbols:   ".objc_class_name_cllocationmanager", referenced from:       literal-pointer@__objc@__cls_refs@cllocationmanager in mapviewcontroller.o   "_kcllocationaccuracynearesttenmeters", referenced from:       _kcllocationaccuracynearesttenmeters$non_lazy_ptr in mapviewcontroller.o ld: symbol(s) not found collect2: ld returned 1 exit status 

here;s code:

mapviewcontroller.m  // //  mapviewcontroller.m //  map // //  created ashutosh tiwari on 7/23/10. //  copyright isu 2010. rights reserved. // #import <mapkit/mapkit.h> #import "mapviewcontroller.h"  @implementation mapviewcontroller   // implement viewdidload additional setup after loading view, typically nib. - (void)viewdidload {     cllocationmanager *locationmanager = [[[cllocationmanager alloc] init] autorelease];     locationmanager.delegate = self;     locationmanager.desiredaccuracy = kcllocationaccuracynearesttenmeters;     [locationmanager startupdatinglocation];      [super viewdidload]; }  - (void)locationmanager:(cllocationmanager *)manager didupdatetolocation:(cllocation *)newlocation fromlocation:(cllocation *)oldlocation  {      mkreversegeocoder *geocoder = [[mkreversegeocoder alloc] initwithcoordinate:newlocation.coordinate];     geocoder.delegate = self;     [geocoder start]; }  - (void)locationmanager:(cllocationmanager *)manager didfailwitherror:(nserror *)error  {     nslog(@"locationmanager:%@ didfailwitherror:%@", manager, error); }  - (void)reversegeocoder:(mkreversegeocoder *)geocoder didfindplacemark:(mkplacemark *)placemark {     mkplacemark * myplacemark = placemark;      nsstring *kabpersonaddresscitykey;     nsstring *city = [myplacemark.addressdictionary objectforkey:(nsstring*) kabpersonaddresscitykey]; }  - (void)reversegeocoder:(mkreversegeocoder *)geocoder didfailwitherror:(nserror *)error {     nslog(@"reversegeocoder:%@ didfailwitherror:%@", geocoder, error); }  - (void)dealloc {     [super dealloc]; }  @end 

add corelocation.framework link project (target settings/ linked libraries / add / choose corelocation.framework)

add: briefly each method does:

• viewdidload:
  creates cllocationmanager instance , starts updating location - current user coordinates

• locationmanager:didupdatetolocation:
  gets called when cllocationmanager receives user coordinates. can pass them mkreversegeocoder information of user location (country, city etc)

• locationmanager:didfailwitherror: , reversegeocoder:didfailwitherror:
  handle possible errors - log them in current implementation

• reversegeocoder:didfindplacemark:
  gets called when mkreversegeocoder finds info coordinate, can retrieve info need corresponding fields of mkplacemark instance get.

kabpersonaddresscitykey - key string city field in placemark address dictionary. defined in abperson.h header because address fields placemark , abrecord address same. use key may need link addressbook framework well.