---
title: "copyMemory(from:)"
framework: swift
role: symbol
role_heading: Instance Method
path: "swift/unsafemutablerawbufferpointer/copymemory(from:)"
---

# copyMemory(from:)

Copies the bytes from the given buffer to this buffer’s memory.

## Declaration

```swift
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

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<T>.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.