---
name: "bus_describe_intr"
section: "9"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/BUS_DESCRIBE_INTR"
---

# bus\_describe\_intr(9)

associate a description with an active interrupt handler

Part of [BUS\_DESCRIBE\_INTR(9)](/BUS_DESCRIBE_INTR/9.md).

## NAME

**BUS\_DESCRIBE\_INTR**, **bus\_describe\_intr** – associate a description with an active interrupt handler

## SYNOPSIS

**#include \<sys/param.h\>**

**#include \<sys/bus.h\>**

*int*\

**BUS\_DESCRIBE\_INTR**(*device\_t dev*, *device\_t child*, *struct resource \*irq*, *void \*cookie*, *const char \*descr*);

*int*\

**bus\_describe\_intr**(*device\_t dev*, *struct resource \*irq*, *void \*cookie*, *const char \*fmt*, *...*);

## DESCRIPTION

The **BUS\_DESCRIBE\_INTR**() method associates a description with an active interrupt handler. The *cookie* parameter must be the value returned by a successful call to [BUS\_SETUP\_INTR(9)](/BUS_SETUP_INTR/9.md) for the interrupt *irq*.

The **bus\_describe\_intr**() function is a simple wrapper around **BUS\_DESCRIBE\_INTR**(). As a convenience, **bus\_describe\_intr**() allows the caller to use [printf(9)](/printf/9.md) style formatting to build the description string using *fmt*.

When an interrupt handler is established by [BUS\_SETUP\_INTR(9)](/BUS_SETUP_INTR/9.md), the handler is named after the device the handler is established for. This name is then used in various places such as interrupt statistics displayed by [systat(1)](/systat/1.md) and [vmstat(8)](/vmstat/8.md). For devices that use a single interrupt, the device name is sufficiently unique to identify the interrupt handler. However, for devices that use multiple interrupts it can be useful to distinguish the interrupt handlers. When a description is set for an active interrupt handler, a colon followed by the description is appended to the device name to form the interrupt handler name.

## RETURN VALUES

Zero is returned on success, otherwise an appropriate error is returned.

## SEE ALSO

[systat(1)](/systat/1.md), [vmstat(8)](/vmstat/8.md), [BUS\_SETUP\_INTR(9)](/BUS_SETUP_INTR/9.md), [device(9)](/device/9.md), [printf(9)](/printf/9.md)

## HISTORY

The **BUS\_DESCRIBE\_INTR**() method and **bus\_describe\_intr**() functions first appeared in FreeBSD 8.1.

## BUGS

It is not currently possible to remove a description from an active interrupt handler.