-<?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">
+<?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+
- This file is part of systemd.
-
- Copyright 2016 Julian Orth
+ 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>
</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.
+ If <parameter>p</parameter> is not <constant>NULL</constant>, 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. See the table below for a complete list of allowed
+ types.
</para>
+ <table id='format-specifiers'>
+ <title>Item type specifiers</title>
+
+ <tgroup cols='4'>
+ <colspec colname='specifier' />
+ <colspec colname='constant' />
+ <colspec colname='description' />
+ <colspec colname='ctype' />
+ <thead>
+ <row>
+ <entry>Specifier</entry>
+ <entry>Constant</entry>
+ <entry>Description</entry>
+ <entry>Expected C Type</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry><literal>y</literal></entry>
+ <entry><constant>SD_BUS_TYPE_BYTE</constant></entry>
+ <entry>unsigned integer</entry>
+ <entry>uint8_t *</entry>
+ </row>
+
+ <row>
+ <entry><literal>b</literal></entry>
+ <entry><constant>SD_BUS_TYPE_BOOLEAN</constant></entry>
+ <entry>boolean</entry>
+ <entry>int *</entry>
+ </row>
+
+ <row>
+ <entry><literal>n</literal></entry>
+ <entry><constant>SD_BUS_TYPE_INT16</constant></entry>
+ <entry>signed integer</entry>
+ <entry>int16_t *</entry>
+ </row>
+
+ <row>
+ <entry><literal>q</literal></entry>
+ <entry><constant>SD_BUS_TYPE_UINT16</constant></entry>
+ <entry>unsigned integer</entry>
+ <entry>uint16_t *</entry>
+ </row>
+
+ <row>
+ <entry><literal>i</literal></entry>
+ <entry><constant>SD_BUS_TYPE_INT32</constant></entry>
+ <entry>signed integer</entry>
+ <entry>int32_t *</entry>
+ </row>
+
+ <row>
+ <entry><literal>u</literal></entry>
+ <entry><constant>SD_BUS_TYPE_UINT32</constant></entry>
+ <entry>unsigned integer</entry>
+ <entry>uint32_t *</entry>
+ </row>
+
+ <row>
+ <entry><literal>x</literal></entry>
+ <entry><constant>SD_BUS_TYPE_INT64</constant></entry>
+ <entry>signed integer</entry>
+ <entry>int64_t *</entry>
+ </row>
+
+ <row>
+ <entry><literal>t</literal></entry>
+ <entry><constant>SD_BUS_TYPE_UINT64</constant></entry>
+ <entry>unsigned integer</entry>
+ <entry>uint64_t *</entry>
+ </row>
+
+ <row>
+ <entry><literal>d</literal></entry>
+ <entry><constant>SD_BUS_TYPE_DOUBLE</constant></entry>
+ <entry>floating-point</entry>
+ <entry>double *</entry>
+ </row>
+
+ <row>
+ <entry><literal>s</literal></entry>
+ <entry><constant>SD_BUS_TYPE_STRING</constant></entry>
+ <entry>Unicode string</entry>
+ <entry>const char **</entry>
+ </row>
+
+ <row>
+ <entry><literal>o</literal></entry>
+ <entry><constant>SD_BUS_TYPE_OBJECT_PATH</constant></entry>
+ <entry>object path</entry>
+ <entry>const char **</entry>
+ </row>
+
+ <row>
+ <entry><literal>g</literal></entry>
+ <entry><constant>SD_BUS_TYPE_SIGNATURE</constant></entry>
+ <entry>signature</entry>
+ <entry>const char **</entry>
+ </row>
+
+ <row>
+ <entry><literal>h</literal></entry>
+ <entry><constant>SD_BUS_TYPE_UNIX_FD</constant></entry>
+ <entry>UNIX file descriptor</entry>
+ <entry>int *</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
<para>
If there is no object of the specified type at the current position in the
message, an error is returned.
</para>
</refsect1>
+ <refsect1 id='errors'>
+ <title>Errors</title>
+
+ <para>Returned errors may indicate the following problems:</para>
+
+ <variablelist>
+ <varlistentry>
+ <term><constant>-EINVAL</constant></term>
+
+ <listitem><para>Specified type string is invalid or the message parameter is
+ <constant>NULL</constant>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>-ENXIO</constant></term>
+
+ <listitem><para>The message does not contain the specified type at current
+ position.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>-EBADMSG</constant></term>
+
+ <listitem><para>The message cannot be parsed.</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_message_append_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_bus_message_skip</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_bus_message_read</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
projects / thirdparty / systemd.git / blobdiff