What is the difference between Foundation, Darwin, and CoreFoundation?

The Foundation framework is an Obj-C framework part of Swift’s core libraries. It is the root of all NSObject types. Foundation is closed source.

The Core Foundation (CF) framework is a lower level C implemented library part of Swift’s core libraries. It is the root of all CF types. CF objects must have their memory managed manually. CF does not need a Obj-C runtime. CF is open source.

The difference between these two frameworks is mostly that CF has a very limited Object model (it is C based after all). On the backend, foundation and CF can convert between each other toll-free.

Darwin is a bridge to commonly used C functions. It is a superset of CoreFoundation & Foundation. Here is an example of how it might be used with compiler directives for system specific code:

1
2
3
4
5

#if os(macOS) || os(iOS)
import Darwin
#elseif os(Linux)
import Glibc
#endif

There is also Swift standard library, which provides basic types like Strings.

Originally published 04/03/2021 @ https://pittcsc.org/ Discord

Published here on 09/08/2022. Blog published date reflects the original date of publication.