---
title: "captionAdaptor(_:didVendCaption:skippingUnsupportedSourceSyntaxElements:)"
framework: avfoundation
role: symbol
role_heading: Instance Method
path: "avfoundation/avassetreadercaptionvalidationhandling/captionadaptor(_:didvendcaption:skippingunsupportedsourcesyntaxelements:)"
---

# captionAdaptor(_:didVendCaption:skippingUnsupportedSourceSyntaxElements:)

Tells the delegate that the adaptor ignored one or more syntax elements when it created the caption object.

## Declaration

```swift
optional func captionAdaptor(_ adaptor: AVAssetReaderOutputCaptionAdaptor, didVendCaption caption: AVCaption, skippingUnsupportedSourceSyntaxElements syntaxElements: [String])
```

## Parameters

- `adaptor`: The adaptor object.
- `caption`: The vended caption.
- `syntaxElements`: The array of unsupported syntax elements that the adaptor object skipped.