---
title: CFAllocatorCopyDescriptionCallBack
framework: corefoundation
role: symbol
role_heading: Type Alias
path: corefoundation/cfallocatorcopydescriptioncallback
---

# CFAllocatorCopyDescriptionCallBack

A prototype for a function callback that provides a description of the specified data.

## Declaration

```swift
typealias CFAllocatorCopyDescriptionCallBack = (UnsafeRawPointer?) -> Unmanaged<CFString>?
```

## Parameters

- `info`: An untyped pointer to program-defined data.

## Return Value

Return Value A CFString object that describes the allocator. The caller is responsible for releasing this object.

## Discussion

Discussion A prototype for a function callback that provides a description of the data pointed to by the info field. In implementing this function, return a reference to a CFString object that describes your allocator, particularly some characteristics of your program-defined data.

## See Also

### Callbacks

- [CFAllocatorAllocateCallBack](corefoundation/cfallocatorallocatecallback.md)
- [CFAllocatorDeallocateCallBack](corefoundation/cfallocatordeallocatecallback.md)
- [CFAllocatorPreferredSizeCallBack](corefoundation/cfallocatorpreferredsizecallback.md)
- [CFAllocatorReallocateCallBack](corefoundation/cfallocatorreallocatecallback.md)
- [CFAllocatorReleaseCallBack](corefoundation/cfallocatorreleasecallback.md)
- [CFAllocatorRetainCallBack](corefoundation/cfallocatorretaincallback.md)