2 <!DOCTYPE refentry PUBLIC
"-//OASIS//DTD DocBook XML V4.5//EN"
3 "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
4 <!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
6 <refentry id=
"sd_bus_message_read_strv" xmlns:
xi=
"http://www.w3.org/2001/XInclude">
9 <title>sd_bus_message_read_strv
</title>
10 <productname>systemd
</productname>
14 <refentrytitle>sd_bus_message_read_strv
</refentrytitle>
15 <manvolnum>3</manvolnum>
19 <refname>sd_bus_message_read_strv
</refname>
20 <refname>sd_bus_message_read_strv_extend
</refname>
22 <refpurpose>Access an array of strings in a message
</refpurpose>
27 <funcsynopsisinfo>#include
<systemd/sd-bus.h
></funcsynopsisinfo>
30 <funcdef>int
<function>sd_bus_message_read_strv
</function></funcdef>
31 <paramdef>sd_bus_message *
<parameter>m
</parameter></paramdef>
32 <paramdef>char ***
<parameter>l
</parameter></paramdef>
36 <funcdef>int
<function>sd_bus_message_read_strv_extend
</function></funcdef>
37 <paramdef>sd_bus_message *
<parameter>m
</parameter></paramdef>
38 <paramdef>char ***
<parameter>l
</parameter></paramdef>
44 <title>Description
</title>
46 <para><function>sd_bus_message_read_strv()
</function> reads an array of string-like items from the
47 message
<parameter>m
</parameter>. The
"read pointer" in the message must be right before an array of
48 strings (D-Bus type
<literal>as
</literal>), object paths (D-Bus type
<literal>ao
</literal>), or
49 signatures (D-Bus type
<literal>ag
</literal>). On success, a pointer to a
50 <constant>NULL
</constant>-terminated array of strings (strv) is returned in the output parameter
51 <parameter>l
</parameter>. Note that ownership of this array is transferred to the caller. Hence, the
52 caller is responsible for freeing this array and its contents.
</para>
54 <para><function>sd_bus_message_read_strv_extend()
</function> is similar, but the second parameter is an
55 input-output parameter. If
<parameter>*l
</parameter> is
<constant>NULL
</constant>, if behaves identically
56 to
<function>sd_bus_message_read_strv()
</function>. Otherwise,
<parameter>*l
</parameter> must point to a
57 strv, which will be reallocated and extended with additional strings. This function is particularly
58 useful when combining multiple lists of strings in a message or messages into a single array of strings.
63 <title>Return Value
</title>
65 <para>On success, these functions return a non-negative integer. On failure, they return a negative
66 errno-style error code.
</para>
71 <para>Returned errors may indicate the following problems:
</para>
75 <term><constant>-EINVAL
</constant></term>
77 <listitem><para><parameter>m
</parameter> or
<parameter>l
</parameter> are
<constant>NULL
</constant>.
80 <xi:include href=
"version-info.xml" xpointer=
"v246"/></listitem>
84 <term><constant>-EPERM
</constant></term>
86 <listitem><para>The message is not sealed.
</para>
88 <xi:include href=
"version-info.xml" xpointer=
"v246"/></listitem>
92 <term><constant>-EBADMSG
</constant></term>
94 <listitem><para>The message cannot be parsed.
</para>
96 <xi:include href=
"version-info.xml" xpointer=
"v246"/></listitem>
100 <term><constant>-ENXIO
</constant></term>
102 <listitem><para>The message
"read pointer" is not right before an array of the appropriate type.
105 <xi:include href=
"version-info.xml" xpointer=
"v248"/></listitem>
112 <title>History
</title>
113 <para><function>sd_bus_message_read_strv()
</function> was added in version
246.
</para>
114 <para><function>sd_bus_message_read_strv_extend()
</function> was added in version
252.
</para>
118 <title>See Also
</title>
120 <para><simplelist type=
"inline">
121 <member><citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
122 <member><citerefentry><refentrytitle>sd-bus
</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
123 <member><citerefentry><refentrytitle>sd_bus_message_read
</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>