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<?xml version="1.0"?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
<refentry id="libprelude-prelude-msg">
<refmeta>
<refentrytitle id="top_of_page">prelude-msg</refentrytitle>
<manvolnum>3</manvolnum>
<refmiscinfo>LIBPRELUDE Library</refmiscinfo>
</refmeta>
<refnamediv>
<refname>prelude-msg</refname>
<refpurpose>Prelude Messaging API</refpurpose>
<!--[<xref linkend="desc" endterm="desc.title"/>]-->
</refnamediv>
<refsynopsisdiv id="synopsis">
<title id="synopsis.title">Synopsis</title>
<synopsis>
typedef <link linkend="prelude-msg-t">prelude_msg_t</link>;
enum <link linkend="prelude-msg-priority-t">prelude_msg_priority_t</link>;
<link linkend="int">int</link> <link linkend="prelude-msg-read">prelude_msg_read</link> (<link linkend="prelude-msg-t">prelude_msg_t</link> **msg,
<link linkend="prelude-io-t">prelude_io_t</link> *pio);
<link linkend="int">int</link> <link linkend="prelude-msg-forward">prelude_msg_forward</link> (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg,
<link linkend="prelude-io-t">prelude_io_t</link> *dst,
<link linkend="prelude-io-t">prelude_io_t</link> *src);
<link linkend="int">int</link> <link linkend="prelude-msg-get">prelude_msg_get</link> (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg,
<link linkend="uint8-t">uint8_t</link> *tag,
<link linkend="uint32-t">uint32_t</link> *len,
<link linkend="void">void</link> **buf);
<link linkend="void">void</link> <link linkend="prelude-msg-recycle">prelude_msg_recycle</link> (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg);
<link linkend="void">void</link> <link linkend="prelude-msg-mark-end">prelude_msg_mark_end</link> (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg);
<link linkend="int">int</link> <link linkend="prelude-msg-dynamic-new">prelude_msg_dynamic_new</link> (<link linkend="prelude-msg-t">prelude_msg_t</link> **ret,
<link linkend="int">int</link> (*flush_msg_cb) (prelude_msg_t **msg, void *data),
<link linkend="void">void</link> *data);
<link linkend="int">int</link> <link linkend="prelude-msg-new">prelude_msg_new</link> (<link linkend="prelude-msg-t">prelude_msg_t</link> **ret,
<link linkend="size-t">size_t</link> msgcount,
<link linkend="size-t">size_t</link> msglen,
<link linkend="uint8-t">uint8_t</link> tag,
<link linkend="prelude-msg-priority-t">prelude_msg_priority_t</link> priority);
<link linkend="int">int</link> <link linkend="prelude-msg-set">prelude_msg_set</link> (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg,
<link linkend="uint8-t">uint8_t</link> tag,
<link linkend="uint32-t">uint32_t</link> len,
const <link linkend="void">void</link> *data);
<link linkend="int">int</link> <link linkend="prelude-msg-write">prelude_msg_write</link> (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg,
<link linkend="prelude-io-t">prelude_io_t</link> *dst);
<link linkend="void">void</link> <link linkend="prelude-msg-set-tag">prelude_msg_set_tag</link> (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg,
<link linkend="uint8-t">uint8_t</link> tag);
<link linkend="void">void</link> <link linkend="prelude-msg-set-priority">prelude_msg_set_priority</link> (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg,
<link linkend="prelude-msg-priority-t">prelude_msg_priority_t</link> priority);
<link linkend="uint8-t">uint8_t</link> <link linkend="prelude-msg-get-tag">prelude_msg_get_tag</link> (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg);
<link linkend="prelude-msg-priority-t">prelude_msg_priority_t</link> <link linkend="prelude-msg-get-priority">prelude_msg_get_priority</link>
(<link linkend="prelude-msg-t">prelude_msg_t</link> *msg);
<link linkend="uint32-t">uint32_t</link> <link linkend="prelude-msg-get-len">prelude_msg_get_len</link> (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg);
<link linkend="uint32-t">uint32_t</link> <link linkend="prelude-msg-get-datalen">prelude_msg_get_datalen</link> (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg);
</synopsis>
</refsynopsisdiv>
<refsect1 id="desc">
<title id="desc.title">Description</title>
<para>
This Mesaging API is used for differents Prelude program to communicate
together. It feature compatibility between version, and use a way to describe
data similar to XML.
</para>
<para>
The Message header contain the protocol version, which is only to be used
in case the main protocol structure change (compatibility break), The tag
describe the kind of message, The fragment field may be used if a message
is sent in several time, The priority may be used by the receiving end
to priorityze task, The datalen contain the size of the whole message in
network byte order
<programlisting>
8bits 8bits 8bits 8bits 32bits
+--------+--------+--------+----------+------------------------------+
|version | tag |priority| fragment | datalen |
+--------+--------+--------+----------+------------------------------+
</programlisting>
</para>
<para>
Then the message itself contain submessage composed of :
A tag describing the kind of payload, the len of the payload (in network byte order),
the payload itself, and an end of message byte (0xff) in order to resynchronize in
case of problem.
<programlisting>
8bits 32bits 8bits
+--------+--------------------------------+-----------------+--------+
| tag | len | payload | 0xff |
+--------+--------------------------------+-----------------+--------+
</programlisting>
</para>
</refsect1>
<refsect1 id="details">
<title id="details.title">Details</title>
<refsect2>
<title><anchor id="prelude-msg-t" role="typedef"/>prelude_msg_t</title>
<indexterm><primary>prelude_msg_t</primary></indexterm><programlisting>typedef struct prelude_msg prelude_msg_t;
</programlisting>
<para>
</para></refsect2>
<refsect2>
<title><anchor id="prelude-msg-priority-t" role="enum"/>enum prelude_msg_priority_t</title>
<indexterm><primary>prelude_msg_priority_t</primary></indexterm><programlisting>typedef enum {
PRELUDE_MSG_PRIORITY_NONE = 0,
PRELUDE_MSG_PRIORITY_LOW = 1,
PRELUDE_MSG_PRIORITY_MID = 2,
PRELUDE_MSG_PRIORITY_HIGH = 3
} prelude_msg_priority_t;
</programlisting>
<para>
</para></refsect2>
<refsect2>
<title><anchor id="prelude-msg-read" role="function"/>prelude_msg_read ()</title>
<indexterm><primary>prelude_msg_read</primary></indexterm><programlisting><link linkend="int">int</link> prelude_msg_read (<link linkend="prelude-msg-t">prelude_msg_t</link> **msg,
<link linkend="prelude-io-t">prelude_io_t</link> *pio);</programlisting>
<para>
Read a message on <parameter>pio</parameter> into <parameter>msg</parameter>. If <parameter>msg</parameter> is NULL, it is
allocated. This function will never block.</para>
<para>
</para><variablelist role="params">
<varlistentry><term><parameter>msg</parameter> :</term>
<listitem><simpara> Pointer on a <link linkend="prelude-msg-t"><type>prelude_msg_t</type></link> object address.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>pio</parameter> :</term>
<listitem><simpara> Pointer on a <link linkend="prelude-io-t"><type>prelude_io_t</type></link> object.
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> 0 if reading the message is complete, or a <link linkend="prelude-error-t"><type>prelude_error_t</type></link>
error if an error occured. Take particular attention to <link linkend="PRELUDE-ERROR-EAGAIN:CAPS"><type>PRELUDE_ERROR_EAGAIN</type></link>
and PRELUDE_ERROR_EOF.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="prelude-msg-forward" role="function"/>prelude_msg_forward ()</title>
<indexterm><primary>prelude_msg_forward</primary></indexterm><programlisting><link linkend="int">int</link> prelude_msg_forward (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg,
<link linkend="prelude-io-t">prelude_io_t</link> *dst,
<link linkend="prelude-io-t">prelude_io_t</link> *src);</programlisting>
<para>
<link linkend="prelude-msg-forward"><function>prelude_msg_forward()</function></link> read the message corresponding to the <parameter>msg</parameter> object
containing the message header previously gathered using <link linkend="prelude-msg-read-header"><function>prelude_msg_read_header()</function></link>
from the <parameter>src</parameter> object, and transfer it to <parameter>dst</parameter>. The header is also transfered.</para>
<para>
</para><variablelist role="params">
<varlistentry><term><parameter>msg</parameter> :</term>
<listitem><simpara> Pointer on a <link linkend="prelude-msg-t"><type>prelude_msg_t</type></link> object containing a message header.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>dst</parameter> :</term>
<listitem><simpara> Pointer on a <link linkend="prelude-io-t"><type>prelude_io_t</type></link> object to send message to.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>src</parameter> :</term>
<listitem><simpara> Pointer on a <link linkend="prelude-io-t"><type>prelude_io_t</type></link> object to read message from.
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> 0 on success, or a negative value if an error occured.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="prelude-msg-get" role="function"/>prelude_msg_get ()</title>
<indexterm><primary>prelude_msg_get</primary></indexterm><programlisting><link linkend="int">int</link> prelude_msg_get (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg,
<link linkend="uint8-t">uint8_t</link> *tag,
<link linkend="uint32-t">uint32_t</link> *len,
<link linkend="void">void</link> **buf);</programlisting>
<para>
<link linkend="prelude-msg-get"><function>prelude_msg_get()</function></link> read the next data chunk contained in the message.
<parameter>tag</parameter> is updated to contain the kind of data the chunk contain.
<parameter>len</parameter> is updated to contain the len of the data chunk.
<parameter>buf</parameter> is updated to point on the data chunk.</para>
<para>
</para><variablelist role="params">
<varlistentry><term><parameter>msg</parameter> :</term>
<listitem><simpara> Pointer on a <link linkend="prelude-msg-t"><type>prelude_msg_t</type></link> object representing the message to get data from.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>tag</parameter> :</term>
<listitem><simpara> Pointer on a 8 bits unsigned integer to store the message tag.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>len</parameter> :</term>
<listitem><simpara> Pointer on a 32 bits unsigned integer to store the message len to.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>buf</parameter> :</term>
<listitem><simpara> Address of a pointer to store the buffer starting address.
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> 0 on success, or a <link linkend="prelude-error-t"><type>prelude_error_t</type></link> value on error.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="prelude-msg-recycle" role="function"/>prelude_msg_recycle ()</title>
<indexterm><primary>prelude_msg_recycle</primary></indexterm><programlisting><link linkend="void">void</link> prelude_msg_recycle (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg);</programlisting>
<para>
Recycle <parameter>msg</parameter> so you can write at it again, even
thought it was written.</para>
<para>
</para><variablelist role="params">
<varlistentry><term><parameter>msg</parameter> :</term>
<listitem><simpara> Pointer on <link linkend="prelude-msg-t"><type>prelude_msg_t</type></link> object.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="prelude-msg-mark-end" role="function"/>prelude_msg_mark_end ()</title>
<indexterm><primary>prelude_msg_mark_end</primary></indexterm><programlisting><link linkend="void">void</link> prelude_msg_mark_end (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg);</programlisting>
<para>
Mark end of message in the <parameter>msg</parameter> buffer, so you can continue
adding different message in the same buffer.</para>
<para>
</para><variablelist role="params">
<varlistentry><term><parameter>msg</parameter> :</term>
<listitem><simpara> Pointer on <link linkend="prelude-msg-t"><type>prelude_msg_t</type></link> object.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="prelude-msg-dynamic-new" role="function"/>prelude_msg_dynamic_new ()</title>
<indexterm><primary>prelude_msg_dynamic_new</primary></indexterm><programlisting><link linkend="int">int</link> prelude_msg_dynamic_new (<link linkend="prelude-msg-t">prelude_msg_t</link> **ret,
<link linkend="int">int</link> (*flush_msg_cb) (prelude_msg_t **msg, void *data),
<link linkend="void">void</link> *data);</programlisting>
<para>
Allocate a new <link linkend="prelude-msg-t"><type>prelude_msg_t</type></link> object. <link linkend="prelude-msg-set"><function>prelude_msg_set()</function></link> can then be used to
add chunk of data to the message, and <link linkend="prelude-msg-mark-start"><function>prelude_msg_mark_start()</function></link> to separate
different message in the same buffer.
</para>
<para>
This function use memory chunk of static size to store the message in. If
the size of the data you want to store is bigger than the actual chunk size,
<parameter>flush_msg_cb</parameter> callback will be called for the current message to be flushed,
and the returned message will be used in order to store remaining data.</para>
<para>
</para><variablelist role="params">
<varlistentry><term><parameter>ret</parameter> :</term>
<listitem><simpara> Pointer where to store the create <link linkend="prelude-msg-t"><type>prelude_msg_t</type></link>.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>flush_msg_cb</parameter> :</term>
<listitem><simpara> Callback function to call when the buffer need to be flushed.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>data</parameter> :</term>
<listitem><simpara> Data to pass to the <parameter>flush_msg_cb</parameter> callback function.
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> 0 on success, a negative value if an error occured.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="prelude-msg-new" role="function"/>prelude_msg_new ()</title>
<indexterm><primary>prelude_msg_new</primary></indexterm><programlisting><link linkend="int">int</link> prelude_msg_new (<link linkend="prelude-msg-t">prelude_msg_t</link> **ret,
<link linkend="size-t">size_t</link> msgcount,
<link linkend="size-t">size_t</link> msglen,
<link linkend="uint8-t">uint8_t</link> tag,
<link linkend="prelude-msg-priority-t">prelude_msg_priority_t</link> priority);</programlisting>
<para>
Allocate a new <link linkend="prelude-msg-t"><type>prelude_msg_t</type></link> object and store it into <parameter>ret</parameter>. <link linkend="prelude-msg-set"><function>prelude_msg_set()</function></link>
can then be used to add chunk of data to the message, and <link linkend="prelude-msg-write"><function>prelude_msg_write()</function></link>
to send it.</para>
<para>
</para><variablelist role="params">
<varlistentry><term><parameter>ret</parameter> :</term>
<listitem><simpara> Pointer where to store the created <link linkend="prelude-msg-t"><type>prelude_msg_t</type></link>.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>msgcount</parameter> :</term>
<listitem><simpara> Number of chunk of data the created object can accept.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>msglen</parameter> :</term>
<listitem><simpara> Maximum number of bytes the object should handle for all the chunks.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>tag</parameter> :</term>
<listitem><simpara> A tag identifying the kind of message.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>priority</parameter> :</term>
<listitem><simpara> The priority of this message.
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> 0 on success, a negative value if an error occured.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="prelude-msg-set" role="function"/>prelude_msg_set ()</title>
<indexterm><primary>prelude_msg_set</primary></indexterm><programlisting><link linkend="int">int</link> prelude_msg_set (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg,
<link linkend="uint8-t">uint8_t</link> tag,
<link linkend="uint32-t">uint32_t</link> len,
const <link linkend="void">void</link> *data);</programlisting>
<para>
<link linkend="prelude-msg-set"><function>prelude_msg_set()</function></link> append <parameter>len</parameter> bytes of data from the <parameter>data</parameter> buffer
to the <parameter>msg</parameter> object representing a message. The data is tagged with <parameter>tag</parameter>.</para>
<para>
</para><variablelist role="params">
<varlistentry><term><parameter>msg</parameter> :</term>
<listitem><simpara> Pointer on a <link linkend="prelude-msg-t"><type>prelude_msg_t</type></link> object to store the data to.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>tag</parameter> :</term>
<listitem><simpara> 8 bits unsigned integer describing the kind of data.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>len</parameter> :</term>
<listitem><simpara> len of the data chunk.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>data</parameter> :</term>
<listitem><simpara> Pointer to the starting address of the data.
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> 0 on success, or a negative value if the remaining space is not
available. You might check the return value mostly if using a dynamic message
through <link linkend="prelude-msg-dynamic-new"><function>prelude_msg_dynamic_new()</function></link>
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="prelude-msg-write" role="function"/>prelude_msg_write ()</title>
<indexterm><primary>prelude_msg_write</primary></indexterm><programlisting><link linkend="int">int</link> prelude_msg_write (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg,
<link linkend="prelude-io-t">prelude_io_t</link> *dst);</programlisting>
<para>
<link linkend="prelude-msg-write"><function>prelude_msg_write()</function></link> write the message corresponding to the <parameter>msg</parameter>
object to <parameter>dst</parameter>. The message should have been created using the
<link linkend="prelude-msg-new"><function>prelude_msg_new()</function></link> and <link linkend="prelude-msg-set"><function>prelude_msg_set()</function></link> functions.</para>
<para>
</para><variablelist role="params">
<varlistentry><term><parameter>msg</parameter> :</term>
<listitem><simpara> Pointer on a <link linkend="prelude-msg-t"><type>prelude_msg_t</type></link> object containing the message.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>dst</parameter> :</term>
<listitem><simpara> Pointer on a <link linkend="prelude-io-t"><type>prelude_io_t</type></link> object to send the message to.
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> 0 on success, or a negative value if an error occured.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="prelude-msg-set-tag" role="function"/>prelude_msg_set_tag ()</title>
<indexterm><primary>prelude_msg_set_tag</primary></indexterm><programlisting><link linkend="void">void</link> prelude_msg_set_tag (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg,
<link linkend="uint8-t">uint8_t</link> tag);</programlisting>
<para>
Tag <parameter>msg</parameter>.</para>
<para>
</para><variablelist role="params">
<varlistentry><term><parameter>msg</parameter> :</term>
<listitem><simpara> Pointer on a <link linkend="prelude-msg-t"><type>prelude_msg_t</type></link> object.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>tag</parameter> :</term>
<listitem><simpara> Tag to associate with <parameter>msg</parameter>.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="prelude-msg-set-priority" role="function"/>prelude_msg_set_priority ()</title>
<indexterm><primary>prelude_msg_set_priority</primary></indexterm><programlisting><link linkend="void">void</link> prelude_msg_set_priority (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg,
<link linkend="prelude-msg-priority-t">prelude_msg_priority_t</link> priority);</programlisting>
<para>
Associate <parameter>priority</parameter> with <parameter>msg</parameter>.</para>
<para>
</para><variablelist role="params">
<varlistentry><term><parameter>msg</parameter> :</term>
<listitem><simpara> Pointer on a <link linkend="prelude-msg-t"><type>prelude_msg_t</type></link> object.
</simpara></listitem></varlistentry>
<varlistentry><term><parameter>priority</parameter> :</term>
<listitem><simpara> Priority to associate with <parameter>msg</parameter>.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="prelude-msg-get-tag" role="function"/>prelude_msg_get_tag ()</title>
<indexterm><primary>prelude_msg_get_tag</primary></indexterm><programlisting><link linkend="uint8-t">uint8_t</link> prelude_msg_get_tag (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg);</programlisting>
<para>
<link linkend="prelude-msg-get-tag"><function>prelude_msg_get_tag()</function></link> return the tag contained in the <parameter>msg</parameter> header.</para>
<para>
</para><variablelist role="params">
<varlistentry><term><parameter>msg</parameter> :</term>
<listitem><simpara> Pointer on a <link linkend="prelude-msg-t"><type>prelude_msg_t</type></link> object.
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> A tag.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="prelude-msg-get-priority" role="function"/>prelude_msg_get_priority ()</title>
<indexterm><primary>prelude_msg_get_priority</primary></indexterm><programlisting><link linkend="prelude-msg-priority-t">prelude_msg_priority_t</link> prelude_msg_get_priority
(<link linkend="prelude-msg-t">prelude_msg_t</link> *msg);</programlisting>
<para>
<link linkend="prelude-msg-get-priority"><function>prelude_msg_get_priority()</function></link> return the priority contained in the <parameter>msg</parameter> header.</para>
<para>
</para><variablelist role="params">
<varlistentry><term><parameter>msg</parameter> :</term>
<listitem><simpara> Pointer on a <link linkend="prelude-msg-t"><type>prelude_msg_t</type></link> object.
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> A priority.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="prelude-msg-get-len" role="function"/>prelude_msg_get_len ()</title>
<indexterm><primary>prelude_msg_get_len</primary></indexterm><programlisting><link linkend="uint32-t">uint32_t</link> prelude_msg_get_len (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg);</programlisting>
<para>
<link linkend="prelude-msg-get-len"><function>prelude_msg_get_len()</function></link> return the currently used
len for the <parameter>msg</parameter> message.</para>
<para>
</para><variablelist role="params">
<varlistentry><term><parameter>msg</parameter> :</term>
<listitem><simpara> Pointer on a <link linkend="prelude-msg-t"><type>prelude_msg_t</type></link> object.
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> Len of the message.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2>
<title><anchor id="prelude-msg-get-datalen" role="function"/>prelude_msg_get_datalen ()</title>
<indexterm><primary>prelude_msg_get_datalen</primary></indexterm><programlisting><link linkend="uint32-t">uint32_t</link> prelude_msg_get_datalen (<link linkend="prelude-msg-t">prelude_msg_t</link> *msg);</programlisting>
<para>
<link linkend="prelude-msg-get-datalen"><function>prelude_msg_get_datalen()</function></link> return the len of the whole message
contained in the <parameter>msg</parameter> header.</para>
<para>
</para><variablelist role="params">
<varlistentry><term><parameter>msg</parameter> :</term>
<listitem><simpara> Pointer on a <link linkend="prelude-msg-t"><type>prelude_msg_t</type></link> object.
</simpara></listitem></varlistentry>
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> Len of the message.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
prelude-msgbuf
</para>
</refsect1>
</refentry>
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