# init(buffer:initializedCount:) Unsafely create an OutputSpan over partly-initialized memory. ``` init(buffer: borrowing Slice>, initializedCount: Int) ``` ## Parameters `buffer` a slice of an `UnsafeMutableBufferPointer` to be initialized `initializedCount` the number of initialized elements at the beginning of `buffer`. ## Discussion The memory in `buffer` must remain valid throughout the lifetime of the newly-created `OutputSpan`. Its prefix must contain `initializedCount` initialized instances, followed by uninitialized memory. The default value of `initializedCount` is 0, representing the common case of a completely uninitialized `buffer`. --- 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)