---
name: "apm"
section: "4"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["linux", "freebsd", "openbsd"]
url: "https://new.carta.tech/apm/4"
---

# apm(4)

power management interface

## NAME

**apm** – power management interface

## DESCRIPTION

**apm** is an interface to power management on i386 and amd64. This interface was originally designed to support the Advanced Power Management (APM) BIOS extension on i386. However, the interface is now implemented by acpi(4.)

**apm** exports an application interface as a character device. Applications such as [apm(8)](/apm/8.md) can control APM, or retrieve APM status information via this interface. The following [ioctl(2)](/ioctl/2.md) commands are defined in ⟨machine/apm\_bios.h⟩:

- **APMIO\_SUSPEND**

  Suspend system (typically using S3).

- **APMIO\_GETINFO**

  Get power management information.

- **APMIO\_STANDBY**

  Suspend system (typically using S1).

- **APMIO\_GETPWSTATUS**

  Get per battery information.

## FILES

- */dev/apm*

  ## SEE ALSO

[apm(8)](/apm/8.md), [zzz(8)](/zzz/8.md)

## AUTHORS

Tatsumi Hosokawa ⟨*hosokawa@jp.FreeBSD.org*⟩