# Core Foundation Access low-level functions, primitive data types, and various collection types that are bridged seamlessly with the Foundation framework. ## Overview Core Foundation is a framework that provides fundamental software services useful to application services, application environments, and to applications themselves. Core Foundation also provides abstractions for common data types, facilitates internationalization with Unicode string storage, and offers a suite of utilities such as plug-in support, XML property lists, URL resource access, and preferences. For more about Core Foundation, see [Core Foundation Design Concepts](https://developer.apple.com/library/archive/documentation/CoreFoundation/Conceptual/CFDesignConcepts/CFDesignConcepts.html#//apple_ref/doc/uid/10000122i). ## Topics ### Utilities [Base Utilities](/documentation/CoreFoundation/base-utilities) [Byte-Order Utilities](/documentation/CoreFoundation/byte-order-utilities) [Core Foundation URL Access Utilities](/documentation/CoreFoundation/core-foundation-url-access-utilities) [Preferences Utilities](/documentation/CoreFoundation/preferences-utilities) [Socket Name Server Utilities](/documentation/CoreFoundation/socket-name-server-utilities) [Time Utilities](/documentation/CoreFoundation/time-utilities) ### Opaque Types [`class CFAllocator`](/documentation/CoreFoundation/CFAllocator) [`class CFArray`](/documentation/CoreFoundation/CFArray) [`class CFAttributedString`](/documentation/CoreFoundation/CFAttributedString) [`class CFBag`](/documentation/CoreFoundation/CFBag) [`class CFBinaryHeap`](/documentation/CoreFoundation/CFBinaryHeap) [`class CFBitVector`](/documentation/CoreFoundation/CFBitVector) [`class CFBoolean`](/documentation/CoreFoundation/CFBoolean) [`class CFBundle`](/documentation/CoreFoundation/CFBundle) [`class CFCalendar`](/documentation/CoreFoundation/CFCalendar) [`class CFCharacterSet`](/documentation/CoreFoundation/CFCharacterSet) [`class CFData`](/documentation/CoreFoundation/CFData) [`class CFDate`](/documentation/CoreFoundation/CFDate) [`class CFDateFormatter`](/documentation/CoreFoundation/CFDateFormatter) [`class CFDictionary`](/documentation/CoreFoundation/CFDictionary) [`class CFError`](/documentation/CoreFoundation/CFError) [`class CFFileDescriptor`](/documentation/CoreFoundation/CFFileDescriptor) [`class CFFileSecurity`](/documentation/CoreFoundation/CFFileSecurity) Encapsulates a file system object’s security information in a Core Foundation object. [`class CFLocale`](/documentation/CoreFoundation/CFLocale) [`class CFMachPort`](/documentation/CoreFoundation/CFMachPort) [`class CFMessagePort`](/documentation/CoreFoundation/CFMessagePort) [`class CFMutableArray`](/documentation/CoreFoundation/CFMutableArray) [`class CFMutableAttributedString`](/documentation/CoreFoundation/CFMutableAttributedString) [`class CFMutableBag`](/documentation/CoreFoundation/CFMutableBag) [`class CFMutableBitVector`](/documentation/CoreFoundation/CFMutableBitVector) [`class CFMutableCharacterSet`](/documentation/CoreFoundation/CFMutableCharacterSet) [`class CFMutableData`](/documentation/CoreFoundation/CFMutableData) [`class CFMutableDictionary`](/documentation/CoreFoundation/CFMutableDictionary) [`class CFMutableSet`](/documentation/CoreFoundation/CFMutableSet) [`class CFMutableString`](/documentation/CoreFoundation/CFMutableString) [`class CFNotificationCenter`](/documentation/CoreFoundation/CFNotificationCenter) [`class CFNull`](/documentation/CoreFoundation/CFNull) [`class CFNumber`](/documentation/CoreFoundation/CFNumber) [`class CFNumberFormatter`](/documentation/CoreFoundation/CFNumberFormatter) [`class CFPlugIn`](/documentation/CoreFoundation/CFPlugIn) [`class CFPlugInInstance`](/documentation/CoreFoundation/CFPlugInInstance) [`typealias CFPropertyList`](/documentation/CoreFoundation/CFPropertyList) [`class CFReadStream`](/documentation/CoreFoundation/CFReadStream) [`class CFRunLoop`](/documentation/CoreFoundation/CFRunLoop) [`class CFRunLoopObserver`](/documentation/CoreFoundation/CFRunLoopObserver) [`class CFRunLoopSource`](/documentation/CoreFoundation/CFRunLoopSource) [`class CFRunLoopTimer`](/documentation/CoreFoundation/CFRunLoopTimer) [`class CFSet`](/documentation/CoreFoundation/CFSet) [`class CFSocket`](/documentation/CoreFoundation/CFSocket) [`class CFString`](/documentation/CoreFoundation/CFString) [`class CFStringTokenizer`](/documentation/CoreFoundation/CFStringTokenizer) [`class CFTimeZone`](/documentation/CoreFoundation/CFTimeZone) [`class CFTree`](/documentation/CoreFoundation/CFTree) [`class CFURL`](/documentation/CoreFoundation/CFURL) [`class CFUserNotification`](/documentation/CoreFoundation/CFUserNotification) [`class CFURLEnumerator`](/documentation/CoreFoundation/CFURLEnumerator) A reference to a `CFURLEnumerator` object. [`class CFUUID`](/documentation/CoreFoundation/CFUUID) [`class CFWriteStream`](/documentation/CoreFoundation/CFWriteStream) [`class CFXMLNode`](/documentation/CoreFoundation/CFXMLNode) [`class CFXMLParser`](/documentation/CoreFoundation/CFXMLParser) [`typealias CFXMLTree`](/documentation/CoreFoundation/CFXMLTree) ### Reference [CFStream](/documentation/CoreFoundation/cfstream) [Core Foundation Structures](/documentation/CoreFoundation/core-foundation-structures) [Core Foundation Enumerations](/documentation/CoreFoundation/core-foundation-enumerations) [Core Foundation Constants](/documentation/CoreFoundation/core-foundation-constants) [Core Foundation Functions](/documentation/CoreFoundation/core-foundation-functions) [Core Foundation Data Types](/documentation/CoreFoundation/core-foundation-data-types) [Core Foundation Macros](/documentation/CoreFoundation/CoreFoundation-macros) ### Variables [`let kCFURLUbiquitousItemIsSyncPausedKey: CFString!`](/documentation/CoreFoundation/kCFURLUbiquitousItemIsSyncPausedKey) [`let kCFURLUbiquitousItemSupportedSyncControlsKey: CFString!`](/documentation/CoreFoundation/kCFURLUbiquitousItemSupportedSyncControlsKey) ### Functions [`func CFAttributedStringGetStatisticalWritingDirections(CFAttributedString!, CFRange, Int8, UnsafeMutablePointer!, UnsafeMutablePointer!) -> Bool`](/documentation/CoreFoundation/CFAttributedStringGetStatisticalWritingDirections(_:_:_:_:_:)) --- Copyright © 2026 Apple Inc. 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