1LIBUDEV(3)                          libudev                         LIBUDEV(3)
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NAME

6       libudev - API for enumerating and introspecting local devices
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SYNOPSIS

9       #include <libudev.h>
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11       pkg-config --cflags --libs libudev
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DESCRIPTION

14       libudev.h provides an API to introspect and enumerate devices on the
15       local system. This library is supported, but should not be used in new
16       projects. Please see sd-device(3) for an equivalent replacement with a
17       more modern API.
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19       All functions require a libudev context to operate. This context can be
20       created via udev_new(3). It is used to track library state and link
21       objects together. No global state is used by libudev, everything is
22       always linked to a udev context.
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24       All functions listed here are thread-agnostic and only a single
25       specific thread may operate on a given object during its entire
26       lifetime. It's safe to allocate multiple independent objects and use
27       each from a specific thread in parallel. However, it's not safe to
28       allocate such an object in one thread, and operate or free it from any
29       other, even if locking is used to ensure these threads don't operate on
30       it at the very same time.
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32       The code described here uses getenv(3), which is declared to be not
33       multi-thread-safe. This means that the code calling the functions
34       described here must not call setenv(3) from a parallel thread. It is
35       recommended to only do calls to setenv() from an early phase of the
36       program when no other threads have been started.
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38       To introspect a local device on a system, a udev device object can be
39       created via udev_device_new_from_syspath(3) and friends. The device
40       object allows one to query current state, read and write attributes and
41       lookup properties of the device in question.
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43       To enumerate local devices on the system, an enumeration object can be
44       created via udev_enumerate_new(3).
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46       To monitor the local system for hotplugged or unplugged devices, a
47       monitor can be created via udev_monitor_new_from_netlink(3).
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49       Whenever libudev returns a list of objects, the udev_list_entry(3) API
50       should be used to iterate, access and modify those lists.
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52       Furthermore, libudev also exports legacy APIs that should not be used
53       by new software (and as such are not documented as part of this
54       manual). This includes the hardware database known as udev_hwdb (please
55       use the new sd-hwdb(3) API instead) and the udev_queue object to query
56       the udev daemon (which should not be used by new software at all).
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SEE ALSO

59       udev_new(3), udev_device_new_from_syspath(3), udev_enumerate_new(3),
60       udev_monitor_new_from_netlink(3), udev_list_entry(3), systemd(1), sd-
61       device(3), sd-hwdb(3), pkg-config(1)
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65systemd 254                                                         LIBUDEV(3)
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