# CFStringInitInlineBuffer(_:_:_:) Initializes an in-line buffer to use for efficient access of a CFString object’s characters. ``` func CFStringInitInlineBuffer(_ str: CFString!, _ buf: UnsafeMutablePointer!, _ range: CFRange) ``` ## Parameters `str` The string to copy to the in-line buffer. `buf` The (uninitialized) [`CFStringInlineBuffer`](/documentation/CoreFoundation/CFStringInlineBuffer) structure to initialize. On return, an initialized structure that can be used in a [`CFStringGetCharacterFromInlineBuffer(_:_:)`](/documentation/CoreFoundation/CFStringGetCharacterFromInlineBuffer(_:_:)) function call. Typically this buffer is allocated on the stack. `range` The range of characters in `str` to copy to `buf`. The specified range must not exceed the length of the string. ## Discussion This function initializes an [`CFStringInlineBuffer`](/documentation/CoreFoundation/CFStringInlineBuffer) structure that can be used for accessing the characters of a string. Once the buffer is initialized you can call the [`CFStringGetCharacterFromInlineBuffer(_:_:)`](/documentation/CoreFoundation/CFStringGetCharacterFromInlineBuffer(_:_:)) function to access the characters in the buffer one at a time. The in-line buffer functions, along with the [`CFStringInlineBuffer`](/documentation/CoreFoundation/CFStringInlineBuffer) structure, give you fast access to the characters of a string. The technique for in-line buffer access combines the convenience of one-at-a-time character access with the efficiency of bulk access. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)