---
title: ABImageClientCallback
framework: Address Book
role: symbol
role_heading: Type Alias
path: addressbook/abimageclientcallback
---

# ABImageClientCallback

Prototype of a callback function used to notify an application when an asynchronous image fetch is complete.

## Declaration

```swift
typealias ABImageClientCallback = (CFData?, CFIndex, UnsafeMutableRawPointer?) -> Void
```

## Parameters

- `imageData`: The image data in Quicktime compatible format that was loaded from an asynchronous fetch. NULL if the fetch failed.
- `tag`: The tracking number for this fetch that should have been obtained from a previous call to the doc://com.apple.addressbook/documentation/AddressBook/ABBeginLoadingImageDataForClient(_:_:_:) function.
- `info`: An untyped pointer to program-defined data that was passed to the doc://com.apple.addressbook/documentation/AddressBook/ABBeginLoadingImageDataForClient(_:_:_:) function.

## Discussion

Discussion Use the ABBeginLoadingImageDataForClient(_:_:_:) function to begin an asynchronous fetch, and the ABCancelLoadingImageDataForTag(_:) function to cancel an asynchronous fetch.