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  "title" : "AssetsLibrary Data Types"
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# AssetsLibrary Data Types

## Topics

### Data Types

[`typedef void (^)(ALAsset *, unsigned long, _Bool *) ALAssetsGroupEnumerationResultsBlock;`](/documentation/AssetsLibrary/ALAssetsGroupEnumerationResultsBlock)

Signature for the block executed during enumeration of assets.

[`typedef NSUInteger ALAssetsGroupType;`](/documentation/AssetsLibrary/ALAssetsGroupType)

A bitfield to identify types of asset.

[`typedef void (^)(NSError *) ALAssetsLibraryAccessFailureBlock;`](/documentation/AssetsLibrary/ALAssetsLibraryAccessFailureBlock)

Signature for the block executed if the user does not grant access to the caller to access the data managed by the framework.

[`typedef void (^)(ALAsset *) ALAssetsLibraryAssetForURLResultBlock;`](/documentation/AssetsLibrary/ALAssetsLibraryAssetForURLResultBlock)

Signature for the block executed if the user has granted access to the caller to access the data managed by the framework in `ALAssetsLibrary/asset(for:resultBlock:failureBlock:)`.

[`typedef void (^)(ALAssetsGroup *) ALAssetsLibraryGroupResultBlock;`](/documentation/AssetsLibrary/ALAssetsLibraryGroupResultBlock)

Signature for the block executed if the user grants access to the caller to access the data managed by the framework..

[`typedef void (^)(ALAssetsGroup *, _Bool *) ALAssetsLibraryGroupsEnumerationResultsBlock;`](/documentation/AssetsLibrary/ALAssetsLibraryGroupsEnumerationResultsBlock)

Signature for the block executed when a match is found during enumeration using `ALAssetsLibrary/enumerateGroups(withTypes:using:failureBlock:)`.

[`typedef void (^)(NSURL *, NSError *) ALAssetsLibraryWriteImageCompletionBlock;`](/documentation/AssetsLibrary/ALAssetsLibraryWriteImageCompletionBlock)

Signature for the block executed when `ALAssetsLibrary/writeImage(toSavedPhotosAlbum:orientation:completionBlock:)` completes.

[`typedef void (^)(NSURL *, NSError *) ALAssetsLibraryWriteVideoCompletionBlock;`](/documentation/AssetsLibrary/ALAssetsLibraryWriteVideoCompletionBlock)

Signature for the block executed when `ALAssetsLibrary/writeVideoAtPath(toSavedPhotosAlbum:completionBlock:)` completes.


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