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# CMTagCollectionApply

Applies a function to all tags in a collection.

```
extern void CMTagCollectionApply(CMTagCollectionRef tagCollection, CMTagCollectionApplierFunction applier, void *context);
```

## Parameters

`tagCollection`

The tag collection to iterate over.

`applier`

The callback function to call for each tag.

`context`

A pointer passed to the `applier` as a parameter on each call.

## Discussion

> Warning:
> When applying a function to a mutable tag collection, modifying `tagCollection` in `applier` causes undefined behavior or a crash.

---

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