# Legacy Map Table Implementation ## Topics ### Functions [`func NSAllMapTableKeys(NSMapTable) -> [Any]`](/documentation/Foundation/NSAllMapTableKeys(_:)) Returns all of the keys in the specified map table. [`func NSAllMapTableValues(NSMapTable) -> [Any]`](/documentation/Foundation/NSAllMapTableValues(_:)) Returns all of the values in the specified table. [`func NSCompareMapTables(NSMapTable, NSMapTable) -> Bool`](/documentation/Foundation/NSCompareMapTables(_:_:)) Compares the elements of two map tables for equality. [`func NSCopyMapTableWithZone(NSMapTable, NSZone?) -> NSMapTable`](/documentation/Foundation/NSCopyMapTableWithZone(_:_:)) Performs a shallow copy of the specified map table. [`func NSCountMapTable(NSMapTable) -> Int`](/documentation/Foundation/NSCountMapTable(_:)) Returns the number of elements in a map table. [`func NSCreateMapTable(NSMapTableKeyCallBacks, NSMapTableValueCallBacks, Int) -> NSMapTable`](/documentation/Foundation/NSCreateMapTable(_:_:_:)) Creates a new map table in the default zone. [`func NSCreateMapTableWithZone(NSMapTableKeyCallBacks, NSMapTableValueCallBacks, Int, NSZone?) -> NSMapTable`](/documentation/Foundation/NSCreateMapTableWithZone(_:_:_:_:)) Creates a new map table in the specified zone. [`func NSEndMapTableEnumeration(UnsafeMutablePointer)`](/documentation/Foundation/NSEndMapTableEnumeration(_:)) Used when finished with an enumerator. [`func NSEnumerateMapTable(NSMapTable) -> NSMapEnumerator`](/documentation/Foundation/NSEnumerateMapTable(_:)) Creates an enumerator for the specified map table. [`func NSFreeMapTable(consuming NSMapTable)`](/documentation/Foundation/NSFreeMapTable(_:)) Deletes the specified map table. [`func NSMapGet(NSMapTable, UnsafeRawPointer?) -> UnsafeMutableRawPointer?`](/documentation/Foundation/NSMapGet(_:_:)) Returns a map table value for the specified key. [`func NSMapInsert(NSMapTable, UnsafeRawPointer?, UnsafeRawPointer?)`](/documentation/Foundation/NSMapInsert(_:_:_:)) Inserts a key-value pair into the specified table. [`func NSMapInsertIfAbsent(NSMapTable, UnsafeRawPointer?, UnsafeRawPointer?) -> UnsafeMutableRawPointer?`](/documentation/Foundation/NSMapInsertIfAbsent(_:_:_:)) Inserts a key-value pair into the specified table. [`func NSMapInsertKnownAbsent(NSMapTable, UnsafeRawPointer?, UnsafeRawPointer?)`](/documentation/Foundation/NSMapInsertKnownAbsent(_:_:_:)) Inserts a key-value pair into the specified table if the pair had not been previously added. [`func NSMapMember(NSMapTable, UnsafeRawPointer, UnsafeMutablePointer?, UnsafeMutablePointer?) -> Bool`](/documentation/Foundation/NSMapMember(_:_:_:_:)) Indicates whether a given table contains a given key. [`func NSMapRemove(NSMapTable, UnsafeRawPointer?)`](/documentation/Foundation/NSMapRemove(_:_:)) Removes a key and corresponding value from the specified table. [`func NSNextMapEnumeratorPair(UnsafeMutablePointer, UnsafeMutablePointer?, UnsafeMutablePointer?) -> Bool`](/documentation/Foundation/NSNextMapEnumeratorPair(_:_:_:)) Returns a Boolean value that indicates whether the next map-table pair in the enumeration are set. [`func NSResetMapTable(NSMapTable)`](/documentation/Foundation/NSResetMapTable(_:)) Deletes the elements of the specified map table. [`func NSStringFromMapTable(NSMapTable) -> String`](/documentation/Foundation/NSStringFromMapTable(_:)) Returns a string describing the map table’s contents. ### Data Types [`struct NSMapEnumerator`](/documentation/Foundation/NSMapEnumerator) Allows successive elements of a map table to be returned each time this structure is passed to [`NSNextMapEnumeratorPair(_:_:_:)`](/documentation/Foundation/NSNextMapEnumeratorPair(_:_:_:)). [NSMapTable](/documentation/Foundation/legacy-nsmaptable) The opaque data type used by the functions described in Managing Map Tables. [`struct NSMapTableKeyCallBacks`](/documentation/Foundation/NSMapTableKeyCallBacks) The function pointers used to configure behavior of `NSMapTable` with respect to key elements within a map table. [`typealias NSMapTableOptions`](/documentation/Foundation/NSMapTableOptions) Constants used as components in a bitfield to specify the behavior of elements (keys and values) in an `NSMapTable` object. [`struct NSMapTableValueCallBacks`](/documentation/Foundation/NSMapTableValueCallBacks) The function pointers used to configure behavior of `NSMapTable` with respect to value elements within a map table. ### Constants [`#define NSNotAnIntMapKey`](/documentation/Foundation/NSNotAnIntMapKey) Predefined `notAKeyMarker` for use with [`NSMapTableKeyCallBacks`](/documentation/Foundation/NSMapTableKeyCallBacks). [`#define NSNotAnIntegerMapKey`](/documentation/Foundation/NSNotAnIntegerMapKey) Predefined `notAKeyMarker` for use with [`NSMapTableKeyCallBacks`](/documentation/Foundation/NSMapTableKeyCallBacks). [`#define NSNotAPointerMapKey`](/documentation/Foundation/NSNotAPointerMapKey) Predefined `notAKeyMarker` for use with [`NSMapTableKeyCallBacks`](/documentation/Foundation/NSMapTableKeyCallBacks). ### Constants [`let NSIntegerMapKeyCallBacks: NSMapTableKeyCallBacks`](/documentation/Foundation/NSIntegerMapKeyCallBacks) For keys that are pointer-sized quantities or smaller (for example, `int`, `long`, or `unichar`). [`let NSIntMapKeyCallBacks: NSMapTableKeyCallBacks`](/documentation/Foundation/NSIntMapKeyCallBacks) For keys that are pointer-sized quantities or smaller (for example, `int`, `long`, or `unichar`). [`let NSNonOwnedPointerMapKeyCallBacks: NSMapTableKeyCallBacks`](/documentation/Foundation/NSNonOwnedPointerMapKeyCallBacks) For keys that are pointers not freed. [`let NSNonOwnedPointerOrNullMapKeyCallBacks: NSMapTableKeyCallBacks`](/documentation/Foundation/NSNonOwnedPointerOrNullMapKeyCallBacks) For keys that are pointers not freed, or `NULL`. [`let NSNonRetainedObjectMapKeyCallBacks: NSMapTableKeyCallBacks`](/documentation/Foundation/NSNonRetainedObjectMapKeyCallBacks) For sets of objects, but without retaining/releasing. [`let NSObjectMapKeyCallBacks: NSMapTableKeyCallBacks`](/documentation/Foundation/NSObjectMapKeyCallBacks) For keys that are objects. [`let NSOwnedPointerMapKeyCallBacks: NSMapTableKeyCallBacks`](/documentation/Foundation/NSOwnedPointerMapKeyCallBacks) For keys that are pointers, with transfer of ownership upon insertion. ### Constants [`let NSIntegerMapValueCallBacks: NSMapTableValueCallBacks`](/documentation/Foundation/NSIntegerMapValueCallBacks) For values that are pointer-sized quantities, (for example, `int`, `long`, or `unichar`). [`let NSIntMapValueCallBacks: NSMapTableValueCallBacks`](/documentation/Foundation/NSIntMapValueCallBacks) For values that are pointer-sized quantities, (for example, `int`, `long`, or `unichar`). [`let NSNonOwnedPointerMapValueCallBacks: NSMapTableValueCallBacks`](/documentation/Foundation/NSNonOwnedPointerMapValueCallBacks) For values that are not owned pointers. [`let NSOwnedPointerMapValueCallBacks: NSMapTableValueCallBacks`](/documentation/Foundation/NSOwnedPointerMapValueCallBacks) For values that are owned pointers. [`let NSNonRetainedObjectMapValueCallBacks: NSMapTableValueCallBacks`](/documentation/Foundation/NSNonRetainedObjectMapValueCallBacks) For sets of objects, but without retaining/releasing. [`let NSObjectMapValueCallBacks: NSMapTableValueCallBacks`](/documentation/Foundation/NSObjectMapValueCallBacks) For values that are objects. --- Copyright © 2026 Apple Inc. 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