---
title: IOUSBDescriptorHeader
framework: IOKit
role: pseudoSymbol
platforms: []
path: iokit/usb_h_user-space/iousbdescriptorheader
---

# IOUSBDescriptorHeader

## Declaration

```occ
struct IOUSBDescriptorHeader {
   UInt8 bLength;
   UInt8 bDescriptorType;
};
```

## Overview

Standard header used for all USB descriptors. Used to read the length of a descriptor so that we can allocate storage for the whole descriptor later on.

## See Also

### Related Documentation

- [IOUSBDescriptorHeader](../../kernel/iousbdescriptorheader.md)