---
title: CFMutableString
framework: corefoundation
role: symbol
role_heading: Class
path: corefoundation/cfmutablestring
---

# CFMutableString

## Declaration

```swift
class CFMutableString
```

## Overview

Overview CFMutableString manages dynamic strings. The basic interface for managing strings is provided by CFString. CFMutableString adds functions to modify the contents of a string. CFMutableString is “toll-free bridged” with its Cocoa Foundation counterpart, NSMutableString. This means that the Core Foundation type is interchangeable in function or method calls with the bridged Foundation object. Therefore, in a method where you see an NSMutableString * parameter, you can pass in a CFMutableStringRef, and in a function where you see a CFMutableStringRef parameter, you can pass in an NSMutableString instance. This also applies to concrete subclasses of NSMutableString. See Toll-Free Bridged Types for more information on toll-free bridging.

## Topics

### CFMutableString Miscellaneous Functions

- [CFStringAppend(_:_:)](corefoundation/cfstringappend(_:_:).md)
- [CFStringAppendCharacters(_:_:_:)](corefoundation/cfstringappendcharacters(_:_:_:).md)
- [CFStringAppendCString(_:_:_:)](corefoundation/cfstringappendcstring(_:_:_:).md)
- [CFStringAppendFormatAndArguments(_:_:_:_:)](corefoundation/cfstringappendformatandarguments(_:_:_:_:).md)
- [CFStringAppendPascalString(_:_:_:)](corefoundation/cfstringappendpascalstring(_:_:_:).md)
- [CFStringCapitalize(_:_:)](corefoundation/cfstringcapitalize(_:_:).md)
- [CFStringCreateMutable(_:_:)](corefoundation/cfstringcreatemutable(_:_:).md)
- [CFStringCreateMutableCopy(_:_:_:)](corefoundation/cfstringcreatemutablecopy(_:_:_:).md)
- [CFStringCreateMutableWithExternalCharactersNoCopy(_:_:_:_:_:)](corefoundation/cfstringcreatemutablewithexternalcharactersnocopy(_:_:_:_:_:).md)
- [CFStringDelete(_:_:)](corefoundation/cfstringdelete(_:_:).md)
- [CFStringFindAndReplace(_:_:_:_:_:)](corefoundation/cfstringfindandreplace(_:_:_:_:_:).md)
- [CFStringFold(_:_:_:)](corefoundation/cfstringfold(_:_:_:).md)
- [CFStringInsert(_:_:_:)](corefoundation/cfstringinsert(_:_:_:).md)
- [CFStringLowercase(_:_:)](corefoundation/cfstringlowercase(_:_:).md)
- [CFStringNormalize(_:_:)](corefoundation/cfstringnormalize(_:_:).md)
- [CFStringPad(_:_:_:_:)](corefoundation/cfstringpad(_:_:_:_:).md)
- [CFStringReplace(_:_:_:)](corefoundation/cfstringreplace(_:_:_:).md)
- [CFStringReplaceAll(_:_:)](corefoundation/cfstringreplaceall(_:_:).md)
- [CFStringSetExternalCharactersNoCopy(_:_:_:_:)](corefoundation/cfstringsetexternalcharactersnocopy(_:_:_:_:).md)
- [CFStringTransform(_:_:_:_:)](corefoundation/cfstringtransform(_:_:_:_:).md)
- [CFStringTrim(_:_:)](corefoundation/cfstringtrim(_:_:).md)
- [CFStringTrimWhitespace(_:)](corefoundation/cfstringtrimwhitespace(_:).md)
- [CFStringUppercase(_:_:)](corefoundation/cfstringuppercase(_:_:).md)

### Constants

- [CFStringNormalizationForm](corefoundation/cfstringnormalizationform.md)
- [Transform Identifiers for CFStringTransform](corefoundation/transform-identifiers-for-cfstringtransform.md)

## Relationships

### Inherits From

- [CFString](corefoundation/cfstring.md)

### Conforms To

- [Equatable](swift/equatable.md)
- [Hashable](swift/hashable.md)

## See Also

### Related Documentation

- [Property List Programming Topics for Core Foundation](apple-archive/documentation/CoreFoundation/Conceptual/CFPropertyLists.md)
- [String Programming Guide for Core Foundation](apple-archive/documentation/CoreFoundation/Conceptual/CFStrings/introCFStrings.html.md)

### Opaque Types

- [CFAllocator](corefoundation/cfallocator.md)
- [CFArray](corefoundation/cfarray.md)
- [CFAttributedString](corefoundation/cfattributedstring.md)
- [CFBag](corefoundation/cfbag.md)
- [CFBinaryHeap](corefoundation/cfbinaryheap.md)
- [CFBitVector](corefoundation/cfbitvector.md)
- [CFBoolean](corefoundation/cfboolean.md)
- [CFBundle](corefoundation/cfbundle.md)
- [CFCalendar](corefoundation/cfcalendar.md)
- [CFCharacterSet](corefoundation/cfcharacterset.md)
- [CFData](corefoundation/cfdata.md)
- [CFDate](corefoundation/cfdate.md)
- [CFDateFormatter](corefoundation/cfdateformatter.md)
- [CFDictionary](corefoundation/cfdictionary.md)
- [CFError](corefoundation/cferror.md)