[ios] IBOutlet and IBAction

IBAction

Type qualifier used by Interface Builder to synchronize actions. Use this type as the return type of any action methods defined in your project. For examples of how to use this identifier, see “Xcode Integration”.

(Also take a loot at target-action patterns)

IBOutlet

Identifier used to identify a property so Interface Builder can synchronize the display and connection of outlets with Xcode. Insert this identifier immediately before the type in any declarations. For examples, including how to use it with the @property syntax, see “Xcode Integration”.

(The type qualifier IBOutlet is a tag applied to an instance-variable declaration so that the Interface Builder application can recognize the instance variable as an outlet and synchronize the display and connection of it with Xcode.)