x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
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 an API to introspect and enumerate devices on the
local system. This library is supported, but should not be used in new
projects. Please see sd-device(3) for an equivalent replacement with a
more modern API.
All functions require a libudev context to operate. This context can be
created 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.
The code described here uses getenv(3), which is declared to be not
multi-thread-safe. This means that the code calling the functions
described here must not call setenv(3) from a parallel thread. It is
recommended to only do calls to setenv() from an early phase of the
program when no other threads have been started.
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 254 LIBUDEV(3)
Want to link to this manual page? Use this URL:
<https://star2.abcm.com/cgi-bin/bsdi-man?query=libudev&sektion=3&manpath=>