<!--
{
  "availability" : [
    "DriverKit: 19.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "USBDriverKit",
  "identifier" : "/documentation/USBDriverKit/IOUSBDeviceCapabilityDescriptorHeader",
  "metadataVersion" : "0.1.0",
  "role" : "Structure",
  "symbol" : {
    "kind" : "Structure",
    "modules" : [
      "USBDriverKit"
    ],
    "preciseIdentifier" : "c:@S@IOUSBDeviceCapabilityDescriptorHeader"
  },
  "title" : "IOUSBDeviceCapabilityDescriptorHeader"
}
-->

# IOUSBDeviceCapabilityDescriptorHeader

The device capability descriptor header.

```
struct IOUSBDeviceCapabilityDescriptorHeader;
```

## Overview

For more information about this descriptor type, see section 9.6.2 of the USB 3.0 specification at <http://www.usb.org>.

## Topics

### Accessing the Descriptor Properties

[`uint8_t bLength;`](/documentation/USBDriverKit/IOUSBDeviceCapabilityDescriptorHeader/bLength)

[`uint8_t bDescriptorType;`](/documentation/USBDriverKit/IOUSBDeviceCapabilityDescriptorHeader/bDescriptorType)

[`uint8_t bDevCapabilityType;`](/documentation/USBDriverKit/IOUSBDeviceCapabilityDescriptorHeader/bDevCapabilityType)


---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)