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systemd/man/sd_bus_message_read_basic.xml
Zbigniew Jędrzejewski-Szmek 11a1589223 tree-wide: drop license boilerplate
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.

I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
2018-04-06 18:58:55 +02:00

103 lines
3.3 KiB
XML

<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
<!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+
This file is part of systemd.
Copyright 2016 Julian Orth
-->
<refentry id="sd_bus_message_read_basic">
<refentryinfo>
<title>sd_bus_message_read_basic</title>
<productname>systemd</productname>
<authorgroup>
<author>
<firstname>Julian</firstname>
<surname>Orth</surname>
<email>ju.orth@gmail.com</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>sd_bus_message_read_basic</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_bus_message_read_basic</refname>
<refpurpose>Read a basic type from a message</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_bus_message_read_basic</function></funcdef>
<paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
<paramdef>char <parameter>type</parameter></paramdef>
<paramdef>void *<parameter>p</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
<function>sd_bus_message_read_basic()</function> reads a basic type from a
message and advances the read position in the message. The set of basic
types and their ascii codes passed in <parameter>type</parameter> are
described in the <ulink
url="https://dbus.freedesktop.org/doc/dbus-specification.html">D-Bus
Specification</ulink>.
</para>
<para>
If <parameter>p</parameter> is not NULL, it should contain a pointer to an
appropriate object. For example, if <parameter>type</parameter> is
<constant>'y'</constant>, the object passed in <parameter>p</parameter>
should have type <code>uint8_t *</code>. If <parameter>type</parameter>
is <constant>'s'</constant>, the object passed in <parameter>p</parameter>
should have type <code>const char **</code>. Note that, if the basic type
is a pointer (e.g., <code>const char *</code> in the case of a string),
the pointer is only borrowed and the contents must be copied if they are
to be used after the end of the messages lifetime. Similarly, during the
lifetime of such a pointer, the message must not be modified.
</para>
<para>
If there is no object of the specified type at the current position in the
message, an error is returned.
</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>
On success, <function>sd_bus_message_read_basic()</function> returns 0 or
a positive integer. On failure, it returns a negative errno-style error
code.
</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
</para>
</refsect1>
</refentry>