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<?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_append_string_memfd"
xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>sd_bus_message_append_string_memfd</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>sd_bus_message_append_string_memfd</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_bus_message_append_string_memfd</refname>
<refname>sd_bus_message_append_string_iovec</refname>
<refname>sd_bus_message_append_string_space</refname>
<refpurpose>Attach a string to a message</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
<funcprototype>
<funcdef>int sd_bus_message_append_string_memfd</funcdef>
<paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
<paramdef>int <parameter>memfd</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int sd_bus_message_append_string_iovec</funcdef>
<paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
<paramdef>const struct iovec *<parameter>iov</parameter></paramdef>
<paramdef>unsigned <parameter>n</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int sd_bus_message_append_string_space</funcdef>
<paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
<paramdef>size_t <parameter>size</parameter></paramdef>
<paramdef>char **<parameter>s</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>The functions
<function>sd_bus_message_append_string_memfd()</function> and
<function>sd_bus_message_append_string_iovec()</function> can be
used to append a single string (item of type <literal>s</literal>)
to message <parameter>m</parameter>.</para>
<para>In case of
<function>sd_bus_message_append_string_memfd()</function>, the
contents of <parameter>memfd</parameter> are the string. They must
satisfy the same constraints as described for the
<literal>s</literal> type in
<citerefentry><refentrytitle>sd_bus_message_append_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
<para>In case of
<function>sd_bus_message_append_string_iovec()</function>, the
payload of <parameter>iov</parameter> is the string. It must
satisfy the same constraints as described for the
<literal>s</literal> type in
<citerefentry><refentrytitle>sd_bus_message_append_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
<para>The <parameter>iov</parameter> argument must point to
<parameter>n</parameter> <structname>struct iovec</structname>
structures. Each structure may have the
<structname>iov_base</structname> field set, in which case the
memory pointed to will be copied into the message, or unset, in
which case a block of spaces (ASCII 32) of length
<structname>iov_len</structname> will be inserted. The
memory pointed at by <parameter>iov</parameter> may be changed
after this call.</para>
<para>The
<function>sd_bus_message_append_string_space()</function> function appends
space for a string to message <parameter>m</parameter>. It behaves
similar to <function>sd_bus_message_append_basic()</function> with
type <literal>s</literal>, but instead of copying a string into
the message, it returns a pointer to the destination area to
the caller in pointer <parameter>p</parameter>. Space for the string
of length <parameter>size</parameter> plus the terminating
<constant>NUL</constant> is allocated.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>On success, those calls return 0 or a positive integer. On failure, they return a negative
errno-style error code.</para>
<xi:include href="sd_bus_message_append_basic.xml" xpointer="errors" />
</refsect1>
<xi:include href="libsystemd-pkgconfig.xml" />
<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>,
<ulink url="https://dbus.freedesktop.org/doc/dbus-specification.html">The D-Bus specification</ulink>
</para>
</refsect1>
</refentry>
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