# copyMemory(from:) Copies the bytes from the given buffer to this buffer’s memory. ``` func copyMemory(from source: UnsafeRawBufferPointer) ``` ## Parameters `source` A buffer of raw bytes. `source.count` must be less than or equal to this buffer’s `count`. ## Discussion If the `source.count` bytes of memory referenced by this buffer are bound to a type `T`, then `T` must be a trivial type, the underlying pointer must be properly aligned for accessing `T`, and `source.count` must be a multiple of `MemoryLayout.stride`. The memory referenced by `source` may overlap with the memory referenced by this buffer. After calling `copyMemory(from:)`, the first `source.count` bytes of memory referenced by this buffer are initialized to raw bytes. If the memory is bound to type `T`, then it contains values of type `T`. --- 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)