---
title: NSHashTableCallBacks
framework: foundation
role: symbol
role_heading: Structure
path: foundation/nshashtablecallbacks
---

# NSHashTableCallBacks

Defines a structure that contains the function pointers used to configure behavior of NSHashTable with respect to elements within a hash table.

## Declaration

```swift
struct NSHashTableCallBacks
```

## Overview

Overview All functions must know the types of things in the hash table to be able to operate on them. Sets of predefined call backs are described in NSHashTable.

## Topics

### Initializers

- [init()](foundation/nshashtablecallbacks/init().md)
- [init(hash:isEqual:retain:release:describe:)](foundation/nshashtablecallbacks/init(hash:isequal:retain:release:describe:).md)

### Instance Properties

- [describe](foundation/nshashtablecallbacks/describe.md)
- [hash](foundation/nshashtablecallbacks/hash.md)
- [isEqual](foundation/nshashtablecallbacks/isequal.md)
- [release](foundation/nshashtablecallbacks/release.md)
- [retain](foundation/nshashtablecallbacks/retain.md)

## Relationships

### Conforms To

- [BitwiseCopyable](swift/bitwisecopyable.md)

## See Also

### Data Types

- [NSHashEnumerator](foundation/nshashenumerator.md)
- [NSHashTableOptions](foundation/nshashtableoptions.md)