# withContiguousMutableStorageIfAvailable(_:) Call `body(buffer)`, where `buffer` provides access to the non-optional contiguous mutable storage of the entire column. If the column contains missing values, `body` is not called and `nil` is returned. ``` mutating func withContiguousMutableStorageIfAvailable(_ body: (inout UnsafeMutableBufferPointer) throws -> R) rethrows -> R? ``` ## Parameters `body` a closure to be executed using the elements of this collection. ## Return Value the value returned by `body`, or `nil`. ## Discussion The optimizer can often eliminate bounds- and uniqueness-checking within an algorithm. When that fails, however, invoking the same algorithm on `body`’s argument may let you trade safety for speed. > Note: `buffer` must not be replaced by `body`. --- 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)