xcode - iOS stop global queue from running -

code:

dispatch_async(       dispatch_get_global_queue(dispatch_queue_priority_background, 0), ^{         [serverapi api_getchatlist:self                         withuserid:[self getuseridfromuserdefaults]                     withscheduleid:strgroupid                           withtype:@"group"];          dispatch_async(dispatch_get_main_queue(), ^{           [self performselector:@selector(getchatlist)                      withobject:nil                      afterdelay:10];          });        }); 

i used dispatch global queue call method every 10 seconds.it working fine.the problem global queue keep running in other controllers too.how stop running?any appreciated.

you can keep bool property,before every call, check property. when want stop, set yes

@property (atomic) bool stop; 

function

-(void)getchatlist {    if (self.stop) {         return;    }  dispatch_async(                dispatch_get_global_queue(dispatch_queue_priority_background, 0), ^{                    //do                    dispatch_async(dispatch_get_main_queue(), ^{                        if (!self.stop) {                             [self performselector:@selector(getchatlist)                                       withobject:nil                                       afterdelay:10];                        }                    });                  }); }