<!--
{
  "availability" : [
    "iOS: 4.0.0 -",
    "iPadOS: 4.0.0 -",
    "macCatalyst: 13.1.0 -",
    "macOS: 10.7.0 -",
    "tvOS: 9.0.0 -",
    "visionOS: 1.0.0 -",
    "watchOS: 6.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "CoreMedia",
  "identifier" : "/documentation/CoreMedia/CMBufferGetBooleanCallback",
  "metadataVersion" : "0.1.0",
  "role" : "Type Alias",
  "symbol" : {
    "kind" : "Type Alias",
    "modules" : [
      "Core Media"
    ],
    "preciseIdentifier" : "c:@T@CMBufferGetBooleanCallback"
  },
  "title" : "CMBufferGetBooleanCallback"
}
-->

# CMBufferGetBooleanCallback

Callback that returns a Boolean value from a `CMBuffer`.

```
typealias CMBufferGetBooleanCallback = (CMBuffer, UnsafeMutableRawPointer?) -> DarwinBoolean
```

## Discussion

There is one callback of this type that can be provided to `Creating Buffer Queues`: `isDataReady` (optional).

### Callback Parameters

- buf: The buffer being interrogated.
- refcon: The contextual data from the client (which may be `NULL`).

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)