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)