<refname>sd_bus_message_append</refname>
<refname>sd_bus_message_appendv</refname>
- <refpurpose>Attach fields to a D-Bus message based on a type
- string</refpurpose>
+ <refpurpose>Attach fields to a D-Bus message based on a type string</refpurpose>
</refnamediv>
<refsynopsisdiv>
</funcprototype>
<funcprototype>
- <funcdef>int sd_bus_message_appendv</funcdef>
-
<paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
-
<paramdef>const char *<parameter>types</parameter></paramdef>
-
<paramdef>va_list <parameter>ap</parameter></paramdef>
+ <funcdef>int sd_bus_message_appendv</funcdef>
+ <paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
+ <paramdef>const char *<parameter>types</parameter></paramdef>
+ <paramdef>va_list <parameter>ap</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<refsect1>
<title>Description</title>
- <para>The <function>sd_bus_message_append()</function> function
- appends a sequence of fields to the D-Bus message object
- <parameter>m</parameter>. The type string
- <parameter>types</parameter> describes the types of the field
- arguments that follow. For each type specified in the type string,
- one or more arguments need to be specified, in the same order as
- declared in the type string.</para>
-
- <para>The type string is composed of the elements shown in the
- table below. It contains zero or more single "complete types".
- Each complete type may be one of the basic types or a fully
- described container type. A container type may be a structure with
- the contained types, a variant, an array with its element type, or
- a dictionary entry with the contained types. The type string is
- <constant>NUL</constant>-terminated.</para>
-
- <para>In case of a basic type, one argument of the corresponding
- type is expected.</para>
-
- <para>A structure is denoted by a sequence of complete types
- between <literal>(</literal> and <literal>)</literal>. This
- sequence cannot be empty — it must contain at least one type.
- Arguments corresponding to this nested sequence follow the same
- rules as if they were not nested.</para>
-
- <para>A variant is denoted by <literal>v</literal>. Corresponding
- arguments must begin with a type string denoting a complete type,
- and following that, arguments corresponding to the specified type.
+ <para>The <function>sd_bus_message_append()</function> function appends a sequence of fields to
+ the D-Bus message object <parameter>m</parameter>. The type string <parameter>types</parameter>
+ describes the types of the field arguments that follow. For each type specified in the type
+ string, one or more arguments need to be specified, in the same order as declared in the type
+ string.</para>
+
+ <para>The type string is composed of the elements shown in the table below. It contains zero or
+ more single "complete types". Each complete type may be one of the basic types or a fully
+ described container type. A container type may be a structure with the contained types, a
+ variant, an array with its element type, or a dictionary entry with the contained types. The
+ type string is <constant>NUL</constant>-terminated.</para>
+
+ <para>In case of a basic type, one argument of the corresponding type is expected.</para>
+
+ <para>A structure is denoted by a sequence of complete types between <literal>(</literal> and
+ <literal>)</literal>. This sequence cannot be empty — it must contain at least one type.
+ Arguments corresponding to this nested sequence follow the same rules as if they were not
+ nested.</para>
+
+ <para>A variant is denoted by <literal>v</literal>. Corresponding arguments must begin with a
+ type string denoting a complete type, and following that, arguments corresponding to the
+ specified type.</para>
+
+ <para>An array is denoted by <literal>a</literal> followed by a complete type. Corresponding
+ arguments must begin with the number of entries in the array, followed by the entries
+ themselves, matching the element type of the array.</para>
+
+ <para>A dictionary is an array of dictionary entries, denoted by <literal>a</literal> followed
+ by a pair of complete types between <literal>{</literal> and <literal>}</literal>. The first of
+ those types must be a basic type. Corresponding arguments must begin with the number of
+ dictionary entries, followed by a pair of values for each entry matching the element type of the
+ dictionary entries.</para>
+
+ <para><function>sd_bus_message_appendv()</function> is equivalent to
+ <function>sd_bus_message_append()</function>, except that it is called with a
+ <literal>va_list</literal> instead of a variable number of arguments. This function does not
+ call the <function>va_end()</function> macro. Because it invokes the
+ <function>va_arg()</function> macro, the value of <parameter>ap</parameter> is undefined after
+ the call.</para>
+
+ <para>For further details on the D-Bus type system, please consult the
+ <ulink url="http://dbus.freedesktop.org/doc/dbus-specification.html#type-system">D-Bus Specification</ulink>.
</para>
- <para>An array is denoted by <literal>a</literal> followed by a
- complete type. Corresponding arguments must begin with the number of
- entries in the array, followed by the entries themselves,
- matching the element type of the array.</para>
-
- <para>A dictionary is an array of dictionary entries, denoted by
- <literal>a</literal> followed by a pair of complete types between
- <literal>{</literal> and <literal>}</literal>. The first of those
- types must be a basic type. Corresponding arguments must begin
- with the number of dictionary entries, followed by a pair of
- values for each entry matching the element type of
- the dictionary entries.</para>
-
- <para>The <function>sd_bus_message_appendv()</function> is equivalent to the
- <function>sd_bus_message_append()</function>, except that it is called with
- a <literal>va_list</literal> instead of a variable number of arguments. This
- function does not call the <function>va_end()</function> macro. Because it
- invokes the <function>va_arg()</function> macro, the value of
- <parameter>ap</parameter> is undefined after the call.</para>
-
- <para>For further details on the D-Bus type system, please consult
- the <ulink
- url="http://dbus.freedesktop.org/doc/dbus-specification.html#type-system">D-Bus
- Specification</ulink>.</para>
-
<table>
<title>Item type specifiers</title>
<constant>NULL</constant>, which is equivalent to an empty string. See
<citerefentry><refentrytitle>sd_bus_message_append_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>
for the precise interpretation of those and other types.</para>
-
</refsect1>
<refsect1>
<para>Append a structure composed of a string and a D-Bus path:</para>
<programlisting>sd_bus_message_append(m, "(so)", "a string", "/a/path");
-</programlisting>
+ </programlisting>
<para>Append an array of UNIX file descriptors:</para>
<programlisting>sd_bus_message_append(m, "ah", 3, STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO);
-</programlisting>
+ </programlisting>
<para>Append a variant, with the real type "g" (signature),
and value "sdbusisgood":</para>
<refsect1>
<title>Return Value</title>
- <para>On success, these functions return 0 or a positive integer. On failure, they return a negative
- errno-style error code.</para>
+ <para>On success, these functions return a non-negative integer. On failure, they return a
+ negative errno-style error code.</para>
<xi:include href="sd_bus_message_append_basic.xml" xpointer="errors" />
</refsect1>
<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_append_array</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ <citerefentry><refentrytitle>sd_bus_message_append_array</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_bus_message_open_container</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
projects / thirdparty / systemd.git / blobdiff