---
title: hash
framework: corefoundation
role: symbol
role_heading: Instance Property
path: corefoundation/cfrunloopsourcecontext1/hash
---

# hash

A hash calculation callback for your program-defined info pointer. Can be NULL.

## Declaration

```swift
var hash: ((UnsafeRawPointer?) -> CFHashCode)!
```

## Parameters

- `info`: The info member of the doc://com.apple.corefoundation/documentation/CoreFoundation/CFRunLoopSourceContext or doc://com.apple.corefoundation/documentation/CoreFoundation/CFRunLoopSourceContext1 structure that was used when creating the run loop source.

## Return Value

Return Value A hash code value for info.

## Discussion

Discussion If a hash callback is not provided for a source, the info pointer is used.