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# init(bytesNoCopy:length:freeWhenDone:)

Initializes a newly allocated data object by adding the given number of bytes from the given buffer.

```
init(bytesNoCopy bytes: UnsafeMutableRawPointer, length: Int, freeWhenDone b: Bool)
```

## Parameters

`bytes`

A buffer containing data for the new object. If `flag` is <doc://com.apple.documentation/documentation/Swift/true>, `bytes` must point to a memory block allocated with `malloc`.

`length`

The number of bytes to hold from `bytes`. This value must not exceed the length of `bytes`.

`b`

If <doc://com.apple.documentation/documentation/Swift/true>, the returned object takes ownership of the `bytes` pointer and frees it on deallocation.

## See Also

[`dataWithBytesNoCopy:length:freeWhenDone:`](/documentation/Foundation/NSData/dataWithBytesNoCopy:length:freeWhenDone:)

Creates a data object that holds a given number of bytes from a given buffer.


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