cocoa - Implementing GameKit.framework on OSX, cannot authenticate localPlayer -

i'm attempting implement gamekit in osx game. unfortunately can't find information how this; tutorials seem ios (though the documentation states "game center available on ios , os x").

everything compiling fine; problem comes when try authenticate local user:

    [[gklocalplayer localplayer] setauthenticatehandler:^(id viewcontroller, nserror *error) {         if(error) {           dlog(@"error: %@",error);// returning error         }         else if(viewcontroller) {           // do here??         }       }]; 

i have 2 problems:

first, handler gets error: error domain=gkerrordomain code=6 "the requested operation not completed because local player has not been authenticated." userinfo=0x10103bc70 {nslocalizeddescription=the requested operation not completed because local player has not been authenticated.}.

second, don't know how present view controller.

on iphone, code works fine: there's no error, , present viewcontroller (which login screen).

i'm sorry, , realize answer year late, in case may still relevant others still asking question myself. ed marty correct, i've discovered works me this.

[[gklocalplayer localplayer] setauthenticatehandler:^(nsviewcontroller < gkviewcontroller >  viewcontroller, nserror *error) {            if(error) {              nslog(@"error: %@",error);           }           else if(viewcontroller) {             gkdialogcontroller *presenter = [gkdialogcontroller shareddialogcontroller];             presenter.parentwindow = mywindow;             [presenter presentviewcontroller:viewcontroller];          } }]; 

the main difference using nsviewcontroller conforming gkviewcontroller instead of id.(also, used nslog instead of dlog, isn't important).

"i have found, however, useless, , presents login dialog before calls handler."

to make sure works, set new game center account through app. when run program , loads window sign in, press "create new apple id" if have apple id. button may not work, if that's case, open game center , press "create new apple id." either way, objective create "sandboxed" game center account, can learn more here: https://developer.apple.com/library/ios/documentation/networkinginternet/conceptual/gamekit_guide/testingyourgamecenter-awaregame/testingyourgamecenter-awaregame.html#//apple_ref/doc/uid/tp40008304-ch17-sw1

you can tell if account sandboxed if when reading terms , conditions, word "sandbox" appears on yellow banner in top left. once again, i'm sorry i'm late, clears topic future viewers.

p.s. i'm sorry code did not format properly.