Core Foundation (also called CF) is a C application programming interface (API) written by Apple for its operating systems, and is a mix of low-level routines and

wrapper function A wrapper function is a function (another word for a ''subroutine'') in a software library or a computer program whose main purpose is to call a second subroutine or a system call with little or no additional computation. Wrapper functions are u ...

s. Most Core Foundation routines follow a certain naming convention that deal with opaque objects, for example CFDictionaryRef for functions whose names begin with CFDictionary, and these objects are often

reference Reference is a relationship between objects in which one object designates, or acts as a means by which to connect to or link to, another object. The first object in this relation is said to ''refer to'' the second object. It is called a '' name'' ...

counted (manually) through CFRetain and CFRelease. Internally, Core Foundation forms the base of the types in the

Objective-C Objective-C is a general-purpose, object-oriented programming language that adds Smalltalk-style messaging to the C programming language. Originally developed by Brad Cox and Tom Love in the early 1980s, it was selected by NeXT for its NeXT ...

standard library and the Carbon API. The most prevalent use of Core Foundation is for passing its own primitive types for data, including raw

byte The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable uni ...

Unicode Unicode, formally The Unicode Standard,The formal version reference is is an information technology standard for the consistent encoding, representation, and handling of text expressed in most of the world's writing systems. The standard, wh ...

strings,

number A number is a mathematical object used to count, measure, and label. The original examples are the natural numbers 1, 2, 3, 4, and so forth. Numbers can be represented in language with number words. More universally, individual numbers c ...

s, calendar dates, and UUIDs, as well as collections such as

arrays An array is a systematic arrangement of similar objects, usually in rows and columns. Things called an array include: {{TOC right Music * In twelve-tone and serial composition, the presentation of simultaneous twelve-tone sets such that the ...

, sets, and dictionaries, to numerous macOS C routines, primarily those that are

GUI The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...

-related. At the operating system level Core Foundation also provides standardized application preferences management through CFPropertyList,

bundle Bundle or Bundling may refer to: * Bundling (packaging), the process of using straps to bundle up items Biology * Bundle of His, a collection of heart muscle cells specialized for electrical conduction * Bundle of Kent, an extra conduction pat ...

handling, run loops,

interprocess communication In computer science, inter-process communication or interprocess communication (IPC) refers specifically to the mechanisms an operating system provides to allow the processes to manage shared data. Typically, applications can use IPC, categoriz ...

through CFMachPort and CFNotificationCenter, and a basic

graphical user interface The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inst ...

message dialog through CFUserNotification. Other parts of the API include utility routines and wrappers around existing APIs for ease of use. Utility routines perform such actions as file system and

network Network, networking and networked may refer to: Science and technology * Network theory, the study of graphs as a representation of relations between discrete objects * Network science, an academic field that studies complex networks Mathematics ...

I/O through CFReadStream, CFWriteStream, and CFURL and

endianness In computing, endianness, also known as byte sex, is the order or sequence of bytes of a word of digital data in computer memory. Endianness is primarily expressed as big-endian (BE) or little-endian (LE). A big-endian system stores the mos ...

translation (Byte Order Utilities). Some examples of wrapper routines include those for Core Foundation's wrapper routines for Unix sockets, the CFSocket API. Some types in Core Foundation are "toll-free bridged", or interchangeable with a simple cast, with those of their

Foundation Kit The Foundation Kit, or just Foundation for short, is an Objective-C framework in the OpenStep specification. It provides basic classes such as wrapper classes and data structure classes. This framework uses the prefix NS (for NeXTSTEP). It is a ...

counterparts. For example, one could create a CFDictionaryRef Core Foundation type, and then later simply use a standard C cast to convert it to its Objective-C counterpart, NSDictionary *, and then use the desired Objective-C methods on that object as one normally would. Core Foundation has a plug-in model () that is based on the Microsoft Component Object Model.

Open source availability

Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, where its wild ancestor, ' ...

used to release most of CF as an open-source project called CFLite that can be used to write cross-platform applications for macOS,

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, w ...

, and

Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for ser ...

. A third-party open-source implementation called OpenCFLite extends the Apple CFLite for building on 32-bit

and

environments. It is maintained by one of the

WebKit WebKit is a browser engine developed by Apple and primarily used in its Safari web browser, as well as on the iOS and iPadOS version of any web browser. WebKit is also used by the BlackBerry Browser, PlayStation consoles beginning from the P ...

developers, but was stalled by 2015. The karaoke platform KJams maintains a fork since 2017. This version, by its programmer David M. Cotter, supports 64-bit systems and has a CFNetwork implementation with

LibreSSL LibreSSL is an open-source implementation of the Transport Layer Security (TLS) protocol. The implementation is named after Secure Sockets Layer (SSL), the deprecated predecessor of TLS, for which support was removed in release 2.3.0. The OpenBSD ...

-based TLS. A fork of OpenCFLite was created by Grant Erickson (an original collaborator with Brent Fulgham on the SourceForge version) in 2021 with a companion port of the CFHost portion of CFNetwork, as OpenCFNetwork. The Swift Corelib Foundation, a fallback version of the

for the Swift programming language for non-Apple platforms, contains a near-full version of the Core Foundation released under Apache License 2.0.

GNUstep GNUstep is a free software implementation of the Cocoa (formerly OpenStep) Objective-C frameworks, widget toolkit, and application development tools for Unix-like operating systems and Microsoft Windows. It is part of the GNU Project. GNUste ...

includes a version of the Core Foundation called "libs-corebase".

References

External links

Core Foundation reference
at

Apple Developer Apple Developer (formerly Apple Developer Connection) is Apple Inc.'s website for software development tools, application programming interfaces (APIs), and technical resources. It contains resources to help software developers write software for ...

OpenCFLite
at SourceForge
CFLite including CFNetwork
works in 64bit, uses LibreSSL (TLS 1.1, 1.2) {{macOS MacOS APIs

Open source availability

See also

References

External links