# update(from:count:) Update this pointer’s initialized memory with the specified number of instances, copied from the given pointer’s memory. ``` func update(from source: UnsafePointer, count: Int) ``` ## Parameters `source` A pointer to at least `count` initialized instances of type `Pointee`. The memory regions referenced by `source` and this pointer may overlap. `count` The number of instances to copy from the memory referenced by `source` to this pointer’s memory. `count` must not be negative. ## Discussion The region of memory starting at this pointer and covering `count` instances of the pointer’s `Pointee` type must be initialized or `Pointee` must be a trivial type. After calling `update(from:count:)`, the region is initialized. > Note: Returns without performing work if `self` and `source` are equal. --- 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)