A reference to a CFMutableString object.
- iOS 2.0+
- macOS 10.0+
- tvOS 9.0+
- watchOS 2.0+
- Core Foundation
The type refers to a CFMutableString object, which “encapsulates” a Unicode string along with its length; the object has the attribute of being mutable, which means that its character contents can be modified. CFString is an opaque type that defines the characteristics and behavior of CFString objects, both immutable and mutable.
CFMutableString derives from CFString. Therefore, you can pass CFMutableString objects into functions accepting CFString objects.