NSMutableCopying protocol declares a method for providing mutable copies of an object. Only classes that define an “immutable vs. mutable” distinction should adopt this protocol. Classes that don’t define such a distinction should adopt
NSMutableCopying declares one method,
mutableCopyWithZone:, but mutable copying is commonly invoked with the convenience method
mutableCopy method is defined for all NSObjects and simply invokes
mutableCopyWithZone: with the default zone.
If a subclass inherits
mutableCopyWithZone: to properly handle its own instance variables, invoking the superclass’s implementation first.
Returns a new instance that’s a mutable copy of the receiver.
zone: NSZone) -> AnyObject
- (id)mutableCopyWithZone:(NSZone *)
This parameter is ignored. Memory zones are no longer used by Objective-C.
The returned object is implicitly retained by the sender, which is responsible for releasing it. The copy returned is mutable whether the original is mutable or not.
Available in OS X v10.0 and later.