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# UserSendCDB

Sends a vendor-specific Command Descriptor Block (CDB) to the device.

```
virtual kern_return_t UserSendCDB(SCSIType00OutParameters command, SCSIType00InParameters *response);
```

## Parameters

`command`

A [`SCSIType00OutParameters`](/documentation/SCSIPeripheralsDriverKit/SCSIType00OutParameters) instance that contains the request information.

`response`

A pointer to a [`SCSIType00InParameters`](/documentation/SCSIPeripheralsDriverKit/SCSIType00InParameters) instance. On return, the framework fills this object with the response data.

## Return Value

A value that indicates the result of sending the CDB. <doc://com.apple.documentation/documentation/DriverKit/kIOReturnSuccess> indicates success. For error definitions, see <doc://com.apple.documentation/documentation/iokit/iokit_constants>.

## Discussion

Call this method to deliver vendor-specific 16-byte commands to the external drive that this dext matches.

---

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