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# CMTagCollectionCreateUnion

Creates a new tag collection containing all tags from two collections without duplicates.

```
extern OSStatus CMTagCollectionCreateUnion(CMTagCollectionRef tagCollection1, CMTagCollectionRef tagCollection2, CMTagCollectionRef*tagCollectionOut);
```

## Parameters

`tagCollection1`

The first of the tag collections to combine.

`tagCollection2`

The second of the tag collections to combine.

`tagCollectionOut`

The output destination for the new tag collection.

## Return Value

Returns `0` on success and a value from Tag Collection Error Codes on failure.

---

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