---
title: "CFCharacterSetCreateMutableCopy(_:_:)"
framework: corefoundation
role: symbol
role_heading: Function
path: "corefoundation/cfcharactersetcreatemutablecopy(_:_:)"
---

# CFCharacterSetCreateMutableCopy(_:_:)

Creates a new mutable character set with the values from another character set.

## Declaration

```swift
func CFCharacterSetCreateMutableCopy(_ alloc: CFAllocator!, _ theSet: CFCharacterSet!) -> CFMutableCharacterSet!
```

## Parameters

- `alloc`: The allocator to use to allocate memory for the new object. Pass NULL or kCFAllocatorDefault to use the current default allocator.
- `theSet`: The character set to copy.

## Return Value

Return Value A new mutable character set containing the same characters as theSet. Ownership follows the The Create Rule.

## See Also

### Creating a Mutable Character Set

- [CFCharacterSetCreateMutable(_:)](corefoundation/cfcharactersetcreatemutable(_:).md)