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man: libudev - add description to udev_device_*

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Tom Gundersen 2015-06-17 19:48:15 +02:00
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1 changed files with 44 additions and 3 deletions
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47
man/udev_device_new_from_syspath.xml
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@ -106,11 +106,52 @@
</funcsynopsis>
</refsynopsisdiv>
<!--<refsect1>
<refsect1>
<title>Description</title>
<para>XXX: Add some description.</para>
</refsect1>-->
<para><function>udev_device_new_from_syspath</function>,
<function>udev_device_new_from_devnum</function>,
<function>udev_device_new_from_subsystem_sysname</function>,
<function>udev_device_new_from_device_id</function>, and
<function>udev_device_new_from_environment</function>
allocate a new udev device object and returns a pointer to it. This
object is opaque and must not be accessed by the caller via different
means than functions provided by libudev. Initially, the reference count
of the device is 1. You can acquire further references, and drop
gained references via <function>udev_device_ref()</function> and
<function>udev_device_unref()</function>. Once the reference count hits 0,
the device object is destroyed and freed.</para>
<para><function>udev_device_new_from_syspath</function>,
<function>udev_device_new_from_devnum</function>,
<function>udev_device_new_from_subsystem_sysname</function>, and
<function>udev_device_new_from_device_id</function>
create the device object based on information found in
<filename>/sys</filename> annotated with properties from the udev-internal
device database. A syspath is any subdirectory of <filename>/sys</filename>,
with the restriction that a subdirectory of <filename>/sys/devices</filename>
(or a symlink to one) represents a real device and as such must contain
a <filename>uevent</filename> file. <function>udev_device_new_from_devnum</function>
takes a device type, which can be <constant>b</constant> for block devices or
<constant>c</constant> for character devices, as well as a devnum (see
<citerefentry><refentrytitle>makedev</refentrytitle><manvolnum>3</manvolnum></citerefentry>).
<function>udev_device_new_from_subsystem_sysname</function> looks up devices based
on the provided subsystem and sysname and
<function>udev_device_new_from_device_id</function> looks up devices based on the provided
device id (see
<citerefentry><refentrytitle>udev_device_get_subsystem</refentrytitle><manvolnum>3</manvolnum></citerefentry>).
</para>
<para><function>udev_device_new_from_environment</function>
creates a device from the current environment (see
<citerefentry><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>).
Each key-value pair is interpreted in the same way as if it was
received in an uevent (see
<citerefentry><refentrytitle>udev_monitor_receive_device</refentrytitle><manvolnum>3</manvolnum></citerefentry>).
The keys <constant>DEVPATH</constant>, <constant>SUBSYSTEM</constant>,
<constant>ACTION</constant>, and <constant>SEQNUM</constant> are mandatory.</para>
</refsect1>
<refsect1>
<title>Return Value</title>