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# GetLength

Returns the length of the memory block represented by this object.

```
kern_return_t GetLength(uint64_t *returnLength);
```

## Parameters

`returnLength`

A variable in which to put the length of the current memory block.

## Return Value

[`kIOReturnSuccess`](/documentation/DriverKit/kIOReturnSuccess) on success, or another value if an error occurs. See [Error Codes](/documentation/DriverKit/error-codes).

## Discussion

This method returns the effective size of the memory block, which might be less than the block’s total capacity.

## See Also

[`virtual kern_return_t SetLength(uint64_t length);`](/documentation/DriverKit/IOBufferMemoryDescriptor/SetLength)

Changes the length of the memory buffer.


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