libudev - Man Page

#include <libudev​.h>

pkg-config --cflags --libs libudev

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 thread may operate on a given object at any given time​. Different threads may access the same object at different times​. Multiple independent objects may be used from different threads in parallel​.

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)​.

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)