LIBUDEV(3) libudev LIBUDEV(3)
NAME
libudev - API for enumerating and introspecting local devices
SYNOPSIS
#include <libudev.h>
pkg-config --cflags --libs libudev
DESCRIPTION
libudev.h provides APIs to introspect and enumerate devices on the
local system.
All functions require a libudev context to operate. This context can be
create via udev_new(3). It is used to track library state and link
objects together. No global state is used by libudev, everything is
always linked to a udev context.
All functions listed here are thread-agnostic and only a single
specific thread may operate on a given object during its entire
lifetime. It's safe to allocate multiple independent objects and use
each from a specific thread in parallel. However, it's not safe to
allocate such an object in one thread, and operate or free it from any
other, even if locking is used to ensure these threads don't operate on
it at the very same time.
To introspect a local device on a system, a udev device object can be
created via udev_device_new_from_syspath(3) and friends. The device
object allows one to query current state, read and write attributes and
lookup properties of the device in question.
To enumerate local devices on the system, an enumeration object can be
created via udev_enumerate_new(3).
To monitor the local system for hotplugged or unplugged devices, a
monitor can be created via udev_monitor_new_from_netlink(3).
Whenever libudev returns a list of objects, the udev_list_entry(3) API
should be used to iterate, access and modify those lists.
Furthermore, libudev also exports legacy APIs that should not be used
by new software (and as such are not documented as part of this
manual). This includes the hardware database known as udev_hwdb (please
use the new sd-hwdb(3) API instead) and the udev_queue object to query
the udev daemon (which should not be used by new software at all).
SEE ALSO
udev_new(3), udev_device_new_from_syspath(3), udev_enumerate_new(3),
udev_monitor_new_from_netlink(3), udev_list_entry(3), systemd(1), sd-
device(3), sd-hwdb(3), pkg-config(1)
systemd 249 LIBUDEV(3)
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