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This part of the copyright blurb stems from the GPL use recommendations: https://www.gnu.org/licenses/gpl-howto.en.html The concept appears to originate in times where version control was per file, instead of per tree, and was a way to glue the files together. Ultimately, we nowadays don't live in that world anymore, and this information is entirely useless anyway, as people are very welcome to copy these files into any projects they like, and they shouldn't have to change bits that are part of our copyright header for that. hence, let's just get rid of this old cruft, and shorten our codebase a bit.
115 lines
4.2 KiB
XML
115 lines
4.2 KiB
XML
<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!--
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SPDX-License-Identifier: LGPL-2.1+
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Copyright 2018 Lennart Poettering
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-->
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<refentry id="sd_bus_get_n_queued_read">
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<refentryinfo>
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<title>sd_bus_get_fd</title>
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<productname>systemd</productname>
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<authorgroup>
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<author>
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<contrib>Developer</contrib>
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<firstname>Lennart</firstname>
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<surname>Poettering</surname>
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<email>lennart@poettering.net</email>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>sd_bus_get_n_queued_read</refentrytitle>
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<manvolnum>3</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>sd_bus_get_n_queued_read</refname>
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<refname>sd_bus_get_n_queued_write</refname>
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<refpurpose>Get the number of pending bus messages in the read and write queues of a bus connection object</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
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<funcprototype>
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<funcdef>int <function>sd_bus_get_n_queued_read</function></funcdef>
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<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
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<paramdef>uint64_t *<parameter>ret</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_bus_get_n_queued_write</function></funcdef>
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<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
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<paramdef>uint64_t *<parameter>ret</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para>
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<function>sd_bus_get_n_queued_read()</function> may be used to query the number of bus messages in the read queue
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of a bus connection object. The read queue contains all messages read from the transport medium (e.g. network
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socket) but not yet processed locally. The function expects two arguments: the bus object to query, and a pointer
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to a 64bit counter variable to write the current queue size to. Use <function>sd_bus_process()</function> in
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order to process queued messages, i.e. to reduce the size of the read queue (as well as, in fact, the write
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queue, see below).
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</para>
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<para>
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Similarly, <function>sd_bus_get_n_queued_write()</function> may be used to query the number of currently pending
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bus messages in the write queue of a bus connection object. The write queue contains all messages enqueued into
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the connection with a call such as <function>sd_bus_send()</function> but not yet written to the transport
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medium. The expected arguments are similar to <function>sd_bus_get_n_queued_read()</function>. Here too, use
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<function>sd_bus_process()</function> to reduce the size of the write queue. Alternatively, use
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<function>sd_bus_flush()</function> to synchronously write out any pending bus messages until the write queue is
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empty.
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</para>
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</refsect1>
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<refsect1>
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<title>Return Value</title>
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<para>On success, these functions return 0 or a positive integer. On failure, they return a negative errno-style
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error code.</para>
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</refsect1>
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<refsect1>
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<title>Errors</title>
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<para>Returned errors may indicate the following problems:</para>
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<variablelist>
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<varlistentry>
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<term><constant>-ECHILD</constant></term>
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<listitem><para>The bus connection was created in a different process.</para></listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<para>
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_process</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_send</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_flush</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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</para>
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</refsect1>
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</refentry>
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