ios - Segue not executing -

i having brain block. after combing database @ loss why segue not executing. took me long enough figure out how reset nsuserdefaults. when did, figured work fine. after all, have set many segues in app. now, 1 nothing.

func isappalreadylaunchedonce()->bool{     let defaults = nsuserdefaults.standarduserdefaults()      if let isappalreadylaunchedonce = defaults.stringforkey("isappalreadylaunchedonce"){         println("app launched")         return true     }else{         defaults.setbool(true, forkey: "isappalreadylaunchedonce")         println("app launched first time")         performseguewithidentifier("showeula", sender: self)         return false     } } 

the log shows "app launched first time" text expect segue execute. however, noting happens. please help. thank you.

try dispatch_async on main_queue. call function in viewwillappear.

func segue() {     dispatch_async(dispatch_get_main_queue(),{         self.performseguewithidentifier("showeula", sender: nil)     }) }