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# CMTagCollectionCreateDifference

Creates a new tag collection with the difference of two existing collections.

```
extern OSStatus CMTagCollectionCreateDifference(CMTagCollectionRef tagCollectionMinuend, CMTagCollectionRef tagCollectionSubtrahend, CMTagCollectionRef*tagCollectionOut);
```

## Parameters

`tagCollectionMinuend`

The tag collection to remove elements from.

`tagCollectionSubtrahend`

The elements to remove from `tagCollectionMinuend`, if present.

`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.

## Discussion

This function is non-commutative, meaning that the ordering of arguments is important. To produce a disjoint collection of tags rather than a difference, use [`CMTagCollectionCreateExclusiveOr`](/documentation/CoreMedia/CMTagCollectionCreateExclusiveOr).

---

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