# methodSignatureForSelector: Returns an `NSMethodSignature` object that contains a description of the method identified by a given selector. ``` - (NSMethodSignature *) methodSignatureForSelector:(SEL) aSelector; ``` ## Parameters `aSelector` A [Selector](https://developer.apple.com/library/archive/documentation/General/Conceptual/DevPedia-CocoaCore/Selector.html#//apple_ref/doc/uid/TP40008195-CH48) that identifies the method for which to return the implementation address. When the receiver is an instance, `aSelector` should identify an instance method; when the receiver is a class, it should identify a class method. ## Return Value An `NSMethodSignature` object that contains a description of the method identified by `aSelector`, or `nil` if the method can’t be found. ## Discussion This method is used in the implementation of protocols. This method is also used in situations where an `NSInvocation` object must be created, such as during message forwarding. If your object maintains a delegate or is capable of handling messages that it does not directly implement, you should override this method to return an appropriate method signature. ## See Also [`- forwardInvocation:`](/documentation/ObjectiveC/NSObject-swift.class/forwardInvocation:) Overridden by subclasses to forward messages to other objects. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)