---
title: CreateIOBuffer
framework: usbdriverkit
role: symbol
role_heading: Instance Method
path: usbdriverkit/iousbhostinterface/createiobuffer
---

# CreateIOBuffer

Allocates a buffer for use during I/O operations.

## Declaration

```occ
virtual kern_return_t CreateIOBuffer(IOOptionBits options, uint64_t capacity, IOBufferMemoryDescriptor **buffer);
```

## Parameters

- `options`: The direction of I/O transfer for the buffer. For a list of possible values, see Memory Buffer Options.
- `capacity`: The size of the buffer to allocate in bytes.
- `buffer`: A pointer to a variable. On success, this variable contains a pointer to a memory descriptor. It’s your responsibility to release this memory descriptor when you finish using it. If an error occurs, the method returns NULL instead.

## Return Value

Return Value kIOReturnSuccess on success, or another value if an error occurs. See Error Codes.

## Discussion

Discussion This method allocates an IOBufferMemoryDescriptor optimized for use by the underlying controller hardware. A buffer allocated by this method isn’t bounced to perform DMA operations.