The difference between these two scheduled method calls - iOS -

i have seen around few times can't seem find difference between 2 ...

[[nsnotificationcenter defaultcenter] addobserver:self                                          selector:@selector(loginviewfetcheduserinfo:)                                              name:fbsdkprofiledidchangenotification                                            object:nil];  - (void)loginviewfetcheduserinfo:(nsnotification *)notification 

and

[[nsnotificationcenter defaultcenter] addobserver:self                                          selector:@selector(loginviewfetcheduserinfo)                                              name:fbsdkprofiledidchangenotification                                            object:nil];  - (void)loginviewfetcheduserinfo 

i know (void)methodname:(type *)newname can pass in value method don't know difference in 2 above , why first 1 (which used in facebook sdk example) on second one.

the first method passes nsnotification object method. way allows access information notification.

[[nsnotificationcenter defaultcenter] addobserver:self                                      selector:@selector(loginviewfetcheduserinfo:)                                          name:fbsdkprofiledidchangenotification                                        nil]; 

for example, if notification posted userinfo dictionary

nsdictionary *userinfo = @{@"blah" : @"foo"}; [[nsnotificationcenter defaultcenter] postnotificationname:fbsdkprofiledidchangenotification object:self userinfo:userinfo]; 

and wanted access userinfo in method. can access sender of notification, notification's object.

- (void)loginviewfetcheduserinfo:(nsnotification *)notification {     nsdictionary *userinfo = notification.userinfo;     nsobject *sender = notification.object; }