mirror of
https://github.com/systemd/systemd.git
synced 2024-12-01 06:13:38 +08:00
104 lines
3.9 KiB
XML
104 lines
3.9 KiB
XML
<?xml version='1.0'?>
|
|
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
|
|
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
|
|
|
|
<!--
|
|
SPDX-License-Identifier: LGPL-2.1+
|
|
-->
|
|
|
|
<refentry id="sd_bus_get_n_queued_read">
|
|
|
|
<refentryinfo>
|
|
<title>sd_bus_get_fd</title>
|
|
<productname>systemd</productname>
|
|
</refentryinfo>
|
|
|
|
<refmeta>
|
|
<refentrytitle>sd_bus_get_n_queued_read</refentrytitle>
|
|
<manvolnum>3</manvolnum>
|
|
</refmeta>
|
|
|
|
<refnamediv>
|
|
<refname>sd_bus_get_n_queued_read</refname>
|
|
<refname>sd_bus_get_n_queued_write</refname>
|
|
|
|
<refpurpose>Get the number of pending bus messages in the read and write queues of a bus connection object</refpurpose>
|
|
</refnamediv>
|
|
|
|
<refsynopsisdiv>
|
|
<funcsynopsis>
|
|
<funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
|
|
|
|
<funcprototype>
|
|
<funcdef>int <function>sd_bus_get_n_queued_read</function></funcdef>
|
|
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
|
|
<paramdef>uint64_t *<parameter>ret</parameter></paramdef>
|
|
</funcprototype>
|
|
|
|
<funcprototype>
|
|
<funcdef>int <function>sd_bus_get_n_queued_write</function></funcdef>
|
|
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
|
|
<paramdef>uint64_t *<parameter>ret</parameter></paramdef>
|
|
</funcprototype>
|
|
</funcsynopsis>
|
|
</refsynopsisdiv>
|
|
|
|
<refsect1>
|
|
<title>Description</title>
|
|
|
|
<para>
|
|
<function>sd_bus_get_n_queued_read()</function> may be used to query the number of bus messages in the read queue
|
|
of a bus connection object. The read queue contains all messages read from the transport medium (e.g. network
|
|
socket) but not yet processed locally. The function expects two arguments: the bus object to query, and a pointer
|
|
to a 64bit counter variable to write the current queue size to. Use <function>sd_bus_process()</function> in
|
|
order to process queued messages, i.e. to reduce the size of the read queue (as well as, in fact, the write
|
|
queue, see below).
|
|
</para>
|
|
|
|
<para>
|
|
Similarly, <function>sd_bus_get_n_queued_write()</function> may be used to query the number of currently pending
|
|
bus messages in the write queue of a bus connection object. The write queue contains all messages enqueued into
|
|
the connection with a call such as <function>sd_bus_send()</function> but not yet written to the transport
|
|
medium. The expected arguments are similar to <function>sd_bus_get_n_queued_read()</function>. Here too, use
|
|
<function>sd_bus_process()</function> to reduce the size of the write queue. Alternatively, use
|
|
<function>sd_bus_flush()</function> to synchronously write out any pending bus messages until the write queue is
|
|
empty.
|
|
</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Return Value</title>
|
|
|
|
<para>On success, these functions return 0 or a positive integer. On failure, they return a negative errno-style
|
|
error code.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Errors</title>
|
|
|
|
<para>Returned errors may indicate the following problems:</para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><constant>-ECHILD</constant></term>
|
|
|
|
<listitem><para>The bus connection was created in a different process.</para></listitem>
|
|
</varlistentry>
|
|
|
|
</variablelist>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>See Also</title>
|
|
|
|
<para>
|
|
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>sd_bus_process</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>sd_bus_send</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>sd_bus_flush</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
|
</para>
|
|
</refsect1>
|
|
|
|
</refentry>
|