---
title: USBToHostLong
framework: IOKit
role: symbol
role_heading: Macro
platforms: [Mac Catalyst 13.0+, macOS 10.0+]
path: iokit/usbtohostlong
---

# USBToHostLong

## Declaration

```occ
#define USBToHostLong
```

## Discussion

Discussion The USB API's use a convention of specifying parameters in the host order. The USB spec specifies that multi-byte items should be formatted in little endian order. The following macros allow one to translate multi-byte values from Host order to USB order and vice versa. There are separate macros for in-kernel use and for user space use.