mirror of
https://github.com/systemd/systemd.git
synced 2024-11-01 00:51:24 +03:00
117 lines
4.6 KiB
XML
117 lines
4.6 KiB
XML
<?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_bus_message_read_array">
|
|
|
|
<refentryinfo>
|
|
<title>sd_bus_message_read_array</title>
|
|
<productname>systemd</productname>
|
|
</refentryinfo>
|
|
|
|
<refmeta>
|
|
<refentrytitle>sd_bus_message_read_array</refentrytitle>
|
|
<manvolnum>3</manvolnum>
|
|
</refmeta>
|
|
|
|
<refnamediv>
|
|
<refname>sd_bus_message_read_array</refname>
|
|
|
|
<refpurpose>Access an array of elements in a message</refpurpose>
|
|
</refnamediv>
|
|
|
|
<refsynopsisdiv>
|
|
<funcsynopsis>
|
|
<funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
|
|
|
|
<funcprototype>
|
|
<funcdef>int <function>sd_bus_message_read_array</function></funcdef>
|
|
<paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
|
|
<paramdef>char <parameter>type</parameter></paramdef>
|
|
<paramdef>const void **<parameter>ptr</parameter></paramdef>
|
|
<paramdef>size_t *<parameter>size</parameter></paramdef>
|
|
</funcprototype>
|
|
</funcsynopsis>
|
|
</refsynopsisdiv>
|
|
|
|
<refsect1>
|
|
<title>Description</title>
|
|
|
|
<para><function>sd_bus_message_read_array()</function> provides access to an array elements in the
|
|
bus message <parameter>m</parameter>. The "read pointer" in the message must be right before an array of type
|
|
<parameter>type</parameter>. As a special case, <parameter>type</parameter> may be
|
|
<constant>NUL</constant>, in which case any trivial type is acceptable. A pointer to the array data is returned
|
|
in the parameter <parameter>ptr</parameter> and the size of array data (in bytes) is returned in the
|
|
parameter <parameter>size</parameter>. If the returned <parameter>size</parameter> parameter is 0, a
|
|
valid non-null pointer will be returned as <parameter>ptr</parameter>, but it may not be
|
|
dereferenced. The data is aligned as appropriate for the data type. The data is part of the message — it
|
|
may not be modified and is valid only as long as the message is referenced. After this function returns,
|
|
the "read pointer" points at the next element after the array.</para>
|
|
|
|
<para>Note that this function only supports arrays of trivial types, i.e. arrays of booleans, the various
|
|
integer types, as well as floating point numbers. In particular it may not be used for arrays of strings,
|
|
structures or similar.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Return Value</title>
|
|
|
|
<para>
|
|
On success and when an array was read, <function>sd_bus_message_read_array()</function> returns an
|
|
integer greater than zero. If invoked while inside a container element (such as an array, e.g. when
|
|
operating on an array of arrays) and the final element of the outer container has been read already and
|
|
the read pointer is thus behind the last element of the outer container this call returns 0 (and the
|
|
returned pointer will be <constant>NULL</constant> and the size will be 0). 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>Specified type is invalid or not a trivial type (see above), or the message
|
|
parameter or one of the output parameters are <constant>NULL</constant>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><constant>-EOPNOTSUPP</constant></term>
|
|
|
|
<listitem><para>The byte order in the message is different than native byte
|
|
order.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><constant>-EPERM</constant></term>
|
|
|
|
<listitem><para>The message is not sealed.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><constant>-EBADMSG</constant></term>
|
|
|
|
<listitem><para>The message cannot be parsed.</para></listitem>
|
|
</varlistentry>
|
|
|
|
</variablelist>
|
|
</refsect2>
|
|
</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_message_read</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>sd_bus_message_read_strv</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
|
</para>
|
|
</refsect1>
|
|
|
|
</refentry>
|