---
title: kIOUSBBufferUnderrunErr
framework: IOKit
role: symbol
role_heading: Macro
platforms: [Mac Catalyst 13.0+, macOS 10.1+]
path: iokit/kiousbbufferunderrunerr
---

# kIOUSBBufferUnderrunErr

## Declaration

```occ
#define kIOUSBBufferUnderrunErr
```

## Discussion

Discussion These errors are returned by the OHCI controller. The # in parenthesis (xx) corresponds to the OHCI Completion Code. For the following Completion codes, we return a generic IOKit error instead of a USB specific error.    Completion Code         Error Returned              Description 9                       kIOReturnUnderrun           (Data Underrun) EP returned less data than max packet size 8                       kIOReturnOverrun            (Data Overrun) Packet too large or more data than buffer 5                       kIOReturnNotResponding      Device Not responding 4                       kIOUSBPipeStalled           Endpoint returned a STALL PID