# resolveInstanceMethod(_:) Dynamically provides an implementation for a given selector for an instance method. ``` class func resolveInstanceMethod(_ sel: Selector!) -> Bool ``` ## Parameters `sel` The name of a selector to resolve. ## Return Value [`YES`](/documentation/ObjectiveC/YES) if the method was found and added to the receiver, otherwise [`NO`](/documentation/ObjectiveC/NO). ## Discussion This method and [`resolveClassMethod(_:)`](/documentation/ObjectiveC/NSObject-swift.class/resolveClassMethod(_:)) allow you to dynamically provide an implementation for a given selector. An Objective-C method is simply a C function that take at least two arguments—`self` and `_cmd`. Using the [`class_addMethod(_:_:_:_:)`](/documentation/ObjectiveC/class_addMethod(_:_:_:_:)) function, you can add a function to a class as a method. Given the following function: ```objc void dynamicMethodIMP(id self, SEL _cmd) { // implementation .... } ``` you can use `resolveInstanceMethod:` to dynamically add it to a class as a method (called `resolveThisMethodDynamically`) like this: ```objc + (BOOL) resolveInstanceMethod:(SEL)aSEL { if (aSEL == @selector(resolveThisMethodDynamically)) { class_addMethod([self class], aSEL, (IMP) dynamicMethodIMP, "v@:"); return YES; } return [super resolveInstanceMethod:aSel]; } ``` ### Special Considerations This method is called before the Objective-C forwarding mechanism is invoked. If [`responds(to:)`](/documentation/ObjectiveC/NSObjectProtocol/responds(to:)) or [`instancesRespond(to:)`](/documentation/ObjectiveC/NSObject-swift.class/instancesRespond(to:)) is invoked, the dynamic method resolver is given the opportunity to provide an `IMP` for the given selector first. --- 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)