---
title: "CMBufferQueueSetValidationCallback(_:callback:refcon:)"
framework: coremedia
role: symbol
role_heading: Function
path: "coremedia/cmbufferqueuesetvalidationcallback(_:callback:refcon:)"
---

# CMBufferQueueSetValidationCallback(_:callback:refcon:)

A validation callback for the queue to call before enqueuing buffers.

## Declaration

```swift
func CMBufferQueueSetValidationCallback(_ queue: CMBufferQueue, callback: CMBufferValidationCallback, refcon: UnsafeMutableRawPointer?) -> OSStatus
```

## Parameters

- `queue`: CMBufferQueue that will use the validation callback.
- `callback`: Callback that will validate each buffer enqueued.
- `refcon`: Context refcon for validation callback.

## Return Value

Return Value A result code. See Result Codes.

## See Also

### Validating a Queue

- [CMBufferQueueSetValidationHandler(_:_:)](coremedia/cmbufferqueuesetvalidationhandler(_:_:).md)
- [CMBufferValidationHandler](coremedia/cmbuffervalidationhandler.md)
- [CMBufferValidationCallback](coremedia/cmbuffervalidationcallback.md)