What does the kCF prefix mean?

Question

Many constants in CoreFoundation have the kCF prefix. What does it mean?

"[…] constants in CoreFoundation" – well, just that. `k` for "constant", `CF` for "CoreFoundation". — The Paramagnetic Croissant, Jul 27 '15 at 06:22

Martin R · Accepted Answer · 2015-07-27T07:06:12.617

In both OS X Frameworks and iOS Frameworks you find a list of system frameworks together with the key prefixes used by the classes, methods, functions, types, or constants of the framework.

This list contains

Name                      Prefix
--------------------------------
...
CFNetwork.framework       CF
...
CoreFoundation.framework  CF
...

So there are actually several frameworks using the "CF" prefix, but Core Foundation is the most "prominent" one.

The "k" prefix for constants is documented in Naming Conventions in "Introduction to Core Foundation Design Concepts" (emphasis added):

A major programming-interface convention in Core Foundation is to use the name of the opaque type that is most closely related to a symbol as the symbol’s prefix. For functions, this prefix identifies not only the type to which the function “belongs” but usually the type of object that is the target of the function’s action. (An exception to this convention are constants, which put “k” before the type prefix.)

As an example, kCFAllocatorMalloc is a constant related to the CFAllocator type which is part of the Core Foundation framework.

Thank you so much for your patient! – Allen Jul 27 '15 at 07:10 — Allen, Jul 27 '15 at 07:10

score 0 · Answer 2 · answered Jul 27 '15 at 06:26

0

k stands for Constant & CF stands for Core Foundation

answered Jul 27 '15 at 06:26

Nilesh Patel

6,318
1
26
40

Any references? Thanks. – Allen Jul 27 '15 at 06:28
I'm a little curious about that why don't use first characters `c` of constant. – Allen Jul 27 '15 at 06:30
I think `k` stands for `key` – sahara108 Jul 27 '15 at 06:52
check the definition... (An exception to this convention are constants, which put “k” before the type prefix.) – Gobi M Sep 18 '15 at 10:56
discussion for 'k' naming - http://stackoverflow.com/questions/9064794/what-does-the-k-stand-for-in-cocoa-constant-names – Gobi M Sep 18 '15 at 11:00

What does the kCF prefix mean?

2 Answers2