# Core Foundation Functions ## Topics ### Functions [`func CFAllocatorAllocateBytes(CFAllocator!, CFIndex, CFOptionFlags) -> UnsafeMutableRawPointer!`](/documentation/CoreFoundation/CFAllocatorAllocateBytes(_:_:_:)) [`func CFAllocatorAllocateTyped(CFAllocator!, CFIndex, CFAllocatorTypeID, CFOptionFlags) -> UnsafeMutableRawPointer!`](/documentation/CoreFoundation/CFAllocatorAllocateTyped(_:_:_:_:)) [`func CFAllocatorReallocateBytes(CFAllocator!, UnsafeMutableRawPointer!, CFIndex, CFOptionFlags) -> UnsafeMutableRawPointer!`](/documentation/CoreFoundation/CFAllocatorReallocateBytes(_:_:_:_:)) [`func CFAllocatorReallocateTyped(CFAllocator!, UnsafeMutableRawPointer!, CFIndex, CFAllocatorTypeID, CFOptionFlags) -> UnsafeMutableRawPointer!`](/documentation/CoreFoundation/CFAllocatorReallocateTyped(_:_:_:_:_:)) [`func CFAttributedStringGetBidiLevelsAndResolvedDirections(CFAttributedString!, CFRange, Int8, UnsafeMutablePointer!, UnsafeMutablePointer!) -> Bool`](/documentation/CoreFoundation/CFAttributedStringGetBidiLevelsAndResolvedDirections(_:_:_:_:_:)) [`extern CFTypeRefCFAutorelease(CFTypeRef arg);`](/documentation/CoreFoundation/CFAutorelease) [`func CFBundleCopyLocalizedStringForLocalizations(CFBundle!, CFString!, CFString!, CFString!, CFArray!) -> CFString!`](/documentation/CoreFoundation/CFBundleCopyLocalizedStringForLocalizations(_:_:_:_:_:)) Returns a localized string from a bundle’s strings file. [`func CFBundleIsArchitectureLoadable(cpu_type_t) -> Bool`](/documentation/CoreFoundation/CFBundleIsArchitectureLoadable(_:)) [`func CFBundleIsExecutableLoadable(CFBundle!) -> Bool`](/documentation/CoreFoundation/CFBundleIsExecutableLoadable(_:)) [`func CFBundleIsExecutableLoadableForURL(CFURL!) -> Bool`](/documentation/CoreFoundation/CFBundleIsExecutableLoadableForURL(_:)) [`func CFCopyHomeDirectoryURL() -> CFURL!`](/documentation/CoreFoundation/CFCopyHomeDirectoryURL()) [`func CFDateFormatterCreateISO8601Formatter(CFAllocator!, CFISO8601DateFormatOptions) -> CFDateFormatter!`](/documentation/CoreFoundation/CFDateFormatterCreateISO8601Formatter(_:_:)) [`func CFFileSecurityClearProperties(CFFileSecurity!, CFFileSecurityClearOptions) -> Bool`](/documentation/CoreFoundation/CFFileSecurityClearProperties(_:_:)) Clears properties from a `CFFileSecurityRef` object. [`func CFFileSecurityCopyAccessControlList(CFFileSecurity!, UnsafeMutablePointer!) -> Bool`](/documentation/CoreFoundation/CFFileSecurityCopyAccessControlList(_:_:)) Copies the access control list associated with a `CFFileSecurityRef` object. [`func CFFileSecurityCopyGroupUUID(CFFileSecurity!, UnsafeMutablePointer?>!) -> Bool`](/documentation/CoreFoundation/CFFileSecurityCopyGroupUUID(_:_:)) Copies the group UUID associated with a `CFFileSecurityRef` object. [`func CFFileSecurityCopyOwnerUUID(CFFileSecurity!, UnsafeMutablePointer?>!) -> Bool`](/documentation/CoreFoundation/CFFileSecurityCopyOwnerUUID(_:_:)) Copies the owner UUID associated with a `CFFileSecurityRef` object. [`func CFFileSecurityCreate(CFAllocator!) -> CFFileSecurity!`](/documentation/CoreFoundation/CFFileSecurityCreate(_:)) Creates a `CFFileSecurityRef` object. [`func CFFileSecurityCreateCopy(CFAllocator!, CFFileSecurity!) -> CFFileSecurity!`](/documentation/CoreFoundation/CFFileSecurityCreateCopy(_:_:)) Creates a copy of a `CFFileSecurityRef` object. [`func CFFileSecurityGetGroup(CFFileSecurity!, UnsafeMutablePointer!) -> Bool`](/documentation/CoreFoundation/CFFileSecurityGetGroup(_:_:)) Gets the group ID associated with a `CFFileSecurityRef` object [`func CFFileSecurityGetMode(CFFileSecurity!, UnsafeMutablePointer!) -> Bool`](/documentation/CoreFoundation/CFFileSecurityGetMode(_:_:)) Gets the file mode associated with a `CFFileSecurityRef` object. [`func CFFileSecurityGetOwner(CFFileSecurity!, UnsafeMutablePointer!) -> Bool`](/documentation/CoreFoundation/CFFileSecurityGetOwner(_:_:)) Gets the owner ID associated with a `CFFileSecurityRef` object. [`func CFFileSecurityGetTypeID() -> CFTypeID`](/documentation/CoreFoundation/CFFileSecurityGetTypeID()) Returns the type identifier for the `CFFileSecurityRef` opaque type. [`func CFFileSecuritySetAccessControlList(CFFileSecurity!, acl_t!) -> Bool`](/documentation/CoreFoundation/CFFileSecuritySetAccessControlList(_:_:)) Sets the access control list associated with a `CFFileSecurityRef` object. [`func CFFileSecuritySetGroup(CFFileSecurity!, gid_t) -> Bool`](/documentation/CoreFoundation/CFFileSecuritySetGroup(_:_:)) Sets the group ID associated with a `CFFileSecurityRef` object. [`func CFFileSecuritySetGroupUUID(CFFileSecurity!, CFUUID!) -> Bool`](/documentation/CoreFoundation/CFFileSecuritySetGroupUUID(_:_:)) Sets the group UUID associated with a `CFFileSecurityRef` object. [`func CFFileSecuritySetMode(CFFileSecurity!, mode_t) -> Bool`](/documentation/CoreFoundation/CFFileSecuritySetMode(_:_:)) Sets the file mode associated with a `CFFileSecurityRef` object. [`func CFFileSecuritySetOwner(CFFileSecurity!, uid_t) -> Bool`](/documentation/CoreFoundation/CFFileSecuritySetOwner(_:_:)) Sets the owner ID associated with a `CFFileSecurityRef` object. [`func CFFileSecuritySetOwnerUUID(CFFileSecurity!, CFUUID!) -> Bool`](/documentation/CoreFoundation/CFFileSecuritySetOwnerUUID(_:_:)) Sets the owner UUID associated with a `CFFileSecurityRef` object. [`func CFReadStreamCopyDispatchQueue(CFReadStream!) -> dispatch_queue_t!`](/documentation/CoreFoundation/CFReadStreamCopyDispatchQueue(_:)) [`func CFReadStreamSetDispatchQueue(CFReadStream!, dispatch_queue_t!)`](/documentation/CoreFoundation/CFReadStreamSetDispatchQueue(_:_:)) [`func CFRunLoopTimerGetTolerance(CFRunLoopTimer!) -> CFTimeInterval`](/documentation/CoreFoundation/CFRunLoopTimerGetTolerance(_:)) [`func CFRunLoopTimerSetTolerance(CFRunLoopTimer!, CFTimeInterval)`](/documentation/CoreFoundation/CFRunLoopTimerSetTolerance(_:_:)) [`extern CFStringRefCFStringCreateStringWithValidatedFormat(CFAllocatorRef alloc, CFDictionaryRef formatOptions, CFStringRef validFormatSpecifiers, CFStringRef format, CFErrorRef*errorPtr, ...);`](/documentation/CoreFoundation/CFStringCreateStringWithValidatedFormat) [`extern CFStringRefCFStringCreateStringWithValidatedFormatAndArguments(CFAllocatorRef alloc, CFDictionaryRef formatOptions, CFStringRef validFormatSpecifiers, CFStringRef format, va_list arguments, CFErrorRef*errorPtr);`](/documentation/CoreFoundation/CFStringCreateStringWithValidatedFormatAndArguments) [`func CFURLEnumeratorCreateForDirectoryURL(CFAllocator!, CFURL!, CFURLEnumeratorOptions, CFArray!) -> CFURLEnumerator!`](/documentation/CoreFoundation/CFURLEnumeratorCreateForDirectoryURL(_:_:_:_:)) Creates and returns a directory enumerator with provided enumerator behavior options and properties to be prefetched. [`func CFURLEnumeratorCreateForMountedVolumes(CFAllocator!, CFURLEnumeratorOptions, CFArray!) -> CFURLEnumerator!`](/documentation/CoreFoundation/CFURLEnumeratorCreateForMountedVolumes(_:_:_:)) Creates and returns a volume enumerator with provided enumerator behavior options and properties to be prefetched. [`func CFURLEnumeratorGetDescendentLevel(CFURLEnumerator!) -> CFIndex`](/documentation/CoreFoundation/CFURLEnumeratorGetDescendentLevel(_:)) Returns the number of levels a recursive directory enumerator has descended. [`func CFURLEnumeratorGetNextURL(CFURLEnumerator!, UnsafeMutablePointer?>!, UnsafeMutablePointer?>!) -> CFURLEnumeratorResult`](/documentation/CoreFoundation/CFURLEnumeratorGetNextURL(_:_:_:)) Advances an enumerator to the next URL. [`func CFURLEnumeratorGetSourceDidChange(CFURLEnumerator!) -> Bool`](/documentation/CoreFoundation/CFURLEnumeratorGetSourceDidChange(_:)) This function is unimplemented, so it performs no operation. [`func CFURLEnumeratorGetTypeID() -> CFTypeID`](/documentation/CoreFoundation/CFURLEnumeratorGetTypeID()) Returns the opaque type identifier for the CFURLEnumerator opaque type. [`func CFURLEnumeratorSkipDescendents(CFURLEnumerator!)`](/documentation/CoreFoundation/CFURLEnumeratorSkipDescendents(_:)) Tells a recursive enumerator not to descend into the directory at the URL that was returned by the most recent call to the [`CFURLEnumeratorGetNextURL(_:_:_:)`](/documentation/CoreFoundation/CFURLEnumeratorGetNextURL(_:_:_:)) function. [`func CFURLIsFileReferenceURL(CFURL!) -> Bool`](/documentation/CoreFoundation/CFURLIsFileReferenceURL(_:)) [`func CFWriteStreamCopyDispatchQueue(CFWriteStream!) -> dispatch_queue_t!`](/documentation/CoreFoundation/CFWriteStreamCopyDispatchQueue(_:)) [`func CFWriteStreamSetDispatchQueue(CFWriteStream!, dispatch_queue_t!)`](/documentation/CoreFoundation/CFWriteStreamSetDispatchQueue(_:_:)) --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)