# withTemporaryAllocation(byteCount:alignment:_:) Provides scoped access to an output raw span with the specified byte count and alignment. ``` func withTemporaryAllocation(byteCount: Int, alignment: Int, _ body: @_lifetime(0: copy 0) (inout OutputRawSpan) throws(E) -> R) throws(E) -> R where E : Error, R : ~Copyable ``` ## Parameters `byteCount` The number of bytes to temporarily allocate. `byteCount` must not be negative. `alignment` The alignment of the new, temporary region of allocated memory, in bytes. `alignment` must be a whole power of 2. `body` A closure to invoke and to which the allocated output raw span should be passed. ## Return Value Whatever is returned by `body`. ## Discussion This function is useful for cheaply allocating raw storage for a brief duration. Storage may be allocated on the heap or on the stack, depending on the required size and alignment. When `body` is called, it is passed an empty `OutputRawSpan`. `body` may append bytes to the output raw span. After `body` returns, deallocation is automatic. > Throws: Whatever is thrown 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)