<?xml version="1.0" encoding="latin1" ?>
<!DOCTYPE erlref SYSTEM "erlref.dtd">
<erlref>
<header>
<copyright>
<year>2003</year><year>2009</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
The contents of this file are subject to the Erlang Public License,
Version 1.1, (the "License"); you may not use this file except in
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Software distributed under the License is distributed on an "AS IS"
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</legalnotice>
<title>megaco_transport</title>
<prepared>Micael Karlberg</prepared>
<responsible>Micael Karlberg</responsible>
<docno></docno>
<approved>Micael Karlberg</approved>
<checked></checked>
<date>2007-06-15</date>
<rev>%VSN%</rev>
<file>megaco_transport.xml</file>
</header>
<module>megaco_transport</module>
<modulesummary>Megaco transport behaviour.</modulesummary>
<description>
<p>The following functions should be exported from a
<c><![CDATA[megaco_transport]]></c> callback module:</p>
<list type="bulleted">
<item>
<p><seealso marker="#send_message">send_message/2</seealso> [<c><![CDATA[mandatory]]></c>]</p>
</item>
<item>
<p><seealso marker="#send_message">send_message/3</seealso> [<c>optional</c>]</p>
</item>
<item>
<p><seealso marker="#resend_message">resend_message/2</seealso> [<c><![CDATA[optional]]></c>]</p>
</item>
<item>
</item>
</list>
<marker id="send_message"></marker>
</description>
<funcs>
<func>
<name>Module:send_message(Handle, Msg) -> ok | {cancel, Reason} | Error</name>
<name>Module:send_message(Handle, Msg, Resend) -> ok | {cancel, Reason} | Error</name>
<fsummary>Send a megaco message.</fsummary>
<type>
<v>Handle = term()</v>
<v>Msg = binary() | iolist()</v>
<v>Resend = boolean()</v>
<v>Reason = term()</v>
<v>Error = term()</v>
</type>
<desc>
<p>Send a megaco message. </p>
<p>If the function returns <c><![CDATA[{cancel, Reason}]]></c>,
this means the transport module decided not to send the message.
This is <em>not</em> an error. No error messages will be issued
and no error counters incremented.
What actions this will result in depends on what kind of
message was sent.
</p>
<p>In the case of requests, megaco will cancel the message in much
the same way as if <c><![CDATA[megaco:cancel]]></c> had been called
(after a successfull send). The information will be propagated
back to the user differently depending on how the request(s) where
issued: For requests issued using
<seealso marker="megaco#call">megaco:call</seealso>, the info
will be delivered in the return value. For requests issued
using <c><![CDATA[megaco:cast]]></c> the info will be delivered
via a call to the callback function
<seealso marker="megaco_user#trans_reply">handle_trans_reply</seealso>. </p>
<p>In the case of reply, megaco will cancel the reply and information
of this will be returned to the user via a call to the
callback function
<seealso marker="megaco_user#trans_ack">handle_trans_ack</seealso>. </p>
<p>The function <c>send_message/3</c> will only be called if the
<seealso marker="megaco#ui_resend_indication">resend_indication</seealso>
config option has been set to the value <c>flag</c>. The third
argument, <c>Resend</c> then indicates if the message send is
a resend or not. </p>
<marker id="resend_message"></marker>
</desc>
</func>
<func>
<name>Module:resend_message(Handle, Msg) -> ok | {cancel, Reason} | Error</name>
<fsummary>Re-send a megaco message.</fsummary>
<type>
<v>Handle = term()</v>
<v>Msg = binary() | iolist()</v>
<v>Reason = term()</v>
<v>Error = term()</v>
</type>
<desc>
<p>Re-send a megaco message. </p>
<p>Note that this function will only be called if the user has set the
<seealso marker="megaco#ui_resend_indication">resend_indication</seealso>
config option to <c><![CDATA[true]]></c><em>and</em> it is in fact a message
resend. If not <em>both</em> of these condition's are meet,
<c><![CDATA[send_message]]></c> will be called. </p>
<p>If the function returns <c><![CDATA[{cancel, Reason}]]></c>, this means the
transport module decided not to send the message.
This is <em>not</em> an error. No error messages will be issued
and no error counters incremented.
What actions this will result in depends on what kind of
message was sent. </p>
<p>In the case of requests, megaco will cancel the message in much
the same way as if <c><![CDATA[megaco:cancel]]></c> had been called
(after a successfull send). The information will be propagated
back to the user differently depending on how the request(s) where
issued: For requests issued using
<seealso marker="megaco#call">megaco:call</seealso>, the info
will be delivered in the return value. For requests issued
using <c><![CDATA[megaco:cast]]></c> the info will be delivered via a call
to the callback function
<seealso marker="megaco_user#trans_reply">handle_trans_reply</seealso>. </p>
<p>In the case of reply, megaco will cancel the reply and information
of this will be returned to the user via a call to the
callback function
<seealso marker="megaco_user#trans_ack">handle_trans_ack</seealso>. </p>
</desc>
</func>
</funcs>
</erlref>
