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Diffstat (limited to 'man/sd_event_get_fd.xml')
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diff --git a/man/sd_event_get_fd.xml b/man/sd_event_get_fd.xml new file mode 100644 index 0000000..a3b11e4 --- /dev/null +++ b/man/sd_event_get_fd.xml @@ -0,0 +1,111 @@ +<?xml version='1.0'?> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> +<!-- SPDX-License-Identifier: LGPL-2.1-or-later --> + +<refentry id="sd_event_get_fd" xmlns:xi="http://www.w3.org/2001/XInclude"> + + <refentryinfo> + <title>sd_event_get_fd</title> + <productname>systemd</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>sd_event_get_fd</refentrytitle> + <manvolnum>3</manvolnum> + </refmeta> + + <refnamediv> + <refname>sd_event_get_fd</refname> + + <refpurpose>Obtain a file descriptor to poll for event loop events</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <systemd/sd-event.h></funcsynopsisinfo> + + <funcprototype> + <funcdef>int <function>sd_event_get_fd</function></funcdef> + <paramdef>sd_event *<parameter>event</parameter></paramdef> + </funcprototype> + + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para><function>sd_event_get_fd()</function> returns the file + descriptor that an event loop object returned by the + <citerefentry><refentrytitle>sd_event_new</refentrytitle><manvolnum>3</manvolnum></citerefentry> + function uses to wait for events. This file descriptor may itself + be polled for + <constant>POLLIN</constant>/<constant>EPOLLIN</constant> + events. This makes it possible to embed an + <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry> + event loop into another, possibly foreign, event loop.</para> + + <para>The returned file descriptor refers to an <citerefentry + project='man-pages'><refentrytitle>epoll</refentrytitle><manvolnum>7</manvolnum></citerefentry> + object. It is recommended not to alter it by invoking + <citerefentry + project='man-pages'><refentrytitle>epoll_ctl</refentrytitle><manvolnum>2</manvolnum></citerefentry> + on it, in order to avoid interference with the event loop's inner + logic and assumptions.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success, <function>sd_event_get_fd()</function> returns a non-negative file descriptor. On + failure, it returns a negative errno-style error code.</para> + + <refsect2> + <title>Errors</title> + + <para>Returned errors may indicate the following problems:</para> + + <variablelist> + <varlistentry> + <term><constant>-EINVAL</constant></term> + + <listitem><para><parameter>event</parameter> is not a valid pointer to an + <structname>sd_event</structname> structure.</para></listitem> + </varlistentry> + + <varlistentry> + <term><constant>-ECHILD</constant></term> + + <listitem><para>The event loop has been created in a different process.</para></listitem> + + </varlistentry> + </variablelist> + </refsect2> + </refsect1> + + <refsect1> + <title>Examples</title> + + <example> + <title>Integration in the GLib event loop</title> + + <programlisting><xi:include href="glib-event-glue.c" parse="text" /></programlisting> + </example> + </refsect1> + + <xi:include href="libsystemd-pkgconfig.xml" /> + + <refsect1> + <title>See Also</title> + + <para> + <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_event_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_event_wait</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry project='man-pages'><refentrytitle>epoll_ctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>, + <citerefentry project='man-pages'><refentrytitle>epoll</refentrytitle><manvolnum>7</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |