---
title: "NSHashInsertKnownAbsent(_:_:)"
framework: foundation
role: symbol
role_heading: Function
path: "foundation/nshashinsertknownabsent(_:_:)"
---

# NSHashInsertKnownAbsent(_:_:)

Adds an element to the specified hash table.

## Declaration

```swift
func NSHashInsertKnownAbsent(_ table: NSHashTable<AnyObject>, _ pointer: UnsafeRawPointer?)
```

## Discussion

Discussion Inserts pointer, which must not be NULL, into table. Unlike NSHashInsert, this function raises NSInvalidArgumentException if table already includes an element that matches pointer.

## See Also

### Related Documentation

- [NSHashRemove(_:_:)](foundation/nshashremove(_:_:).md)
- [NSHashInsert(_:_:)](foundation/nshashinsert(_:_:).md)
- [NSHashInsertIfAbsent(_:_:)](foundation/nshashinsertifabsent(_:_:).md)

### Functions

- [NSAllHashTableObjects(_:)](foundation/nsallhashtableobjects(_:).md)
- [NSCompareHashTables(_:_:)](foundation/nscomparehashtables(_:_:).md)
- [NSCopyHashTableWithZone(_:_:)](foundation/nscopyhashtablewithzone(_:_:).md)
- [NSCountHashTable(_:)](foundation/nscounthashtable(_:).md)
- [NSCreateHashTable(_:_:)](foundation/nscreatehashtable(_:_:).md)
- [NSCreateHashTableWithZone(_:_:_:)](foundation/nscreatehashtablewithzone(_:_:_:).md)
- [NSEndHashTableEnumeration(_:)](foundation/nsendhashtableenumeration(_:).md)
- [NSEnumerateHashTable(_:)](foundation/nsenumeratehashtable(_:).md)
- [NSFreeHashTable(_:)](foundation/nsfreehashtable(_:).md)
- [NSHashGet(_:_:)](foundation/nshashget(_:_:).md)
- [NSHashInsert(_:_:)](foundation/nshashinsert(_:_:).md)
- [NSHashInsertIfAbsent(_:_:)](foundation/nshashinsertifabsent(_:_:).md)
- [NSHashRemove(_:_:)](foundation/nshashremove(_:_:).md)
- [NSNextHashEnumeratorItem(_:)](foundation/nsnexthashenumeratoritem(_:).md)
- [NSResetHashTable(_:)](foundation/nsresethashtable(_:).md)