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<p>A structure representing the payload and attributes of an MQTT message.
<a href="structMQTTAsync__message.html#details">More...</a></p>
<p><code>#include &lt;MQTTAsync.h&gt;</code></p>
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Collaboration diagram for MQTTAsync_message:</div>
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Data Fields</h2></td></tr>
<tr class="memitem:a4621b522c9923c68003d30e9dba9aa4e"><td class="memItemLeft" align="right" valign="top">char&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="structMQTTAsync__message.html#a4621b522c9923c68003d30e9dba9aa4e">struct_id</a> [4]</td></tr>
<tr class="memdesc:a4621b522c9923c68003d30e9dba9aa4e"><td class="mdescLeft">&#160;</td><td class="mdescRight">The eyecatcher for this structure. <a href="structMQTTAsync__message.html#a4621b522c9923c68003d30e9dba9aa4e">More...</a><br /></td></tr>
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<tr class="memitem:af79efdfc9a4e082cbbafaed8fd333ce1"><td class="memItemLeft" align="right" valign="top">int&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="structMQTTAsync__message.html#af79efdfc9a4e082cbbafaed8fd333ce1">struct_version</a></td></tr>
<tr class="memdesc:af79efdfc9a4e082cbbafaed8fd333ce1"><td class="mdescLeft">&#160;</td><td class="mdescRight">The version number of this structure. <a href="structMQTTAsync__message.html#af79efdfc9a4e082cbbafaed8fd333ce1">More...</a><br /></td></tr>
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int&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="structMQTTAsync__message.html#a9271900e2789ff81e382a47842aaee8f">payloadlen</a></td></tr>
<tr class="memdesc:a9271900e2789ff81e382a47842aaee8f"><td class="mdescLeft">&#160;</td><td class="mdescRight">The length of the MQTT message payload in bytes. <br /></td></tr>
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void *&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="structMQTTAsync__message.html#a13d88e9c871b5b39b73370a0784331af">payload</a></td></tr>
<tr class="memdesc:a13d88e9c871b5b39b73370a0784331af"><td class="mdescLeft">&#160;</td><td class="mdescRight">A pointer to the payload of the MQTT message. <br /></td></tr>
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<tr class="memitem:a6e0971dbde0f04b6dd3bfab97ad5cdb7"><td class="memItemLeft" align="right" valign="top">int&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="structMQTTAsync__message.html#a6e0971dbde0f04b6dd3bfab97ad5cdb7">qos</a></td></tr>
<tr class="memdesc:a6e0971dbde0f04b6dd3bfab97ad5cdb7"><td class="mdescLeft">&#160;</td><td class="mdescRight">The quality of service (QoS) assigned to the message. <a href="structMQTTAsync__message.html#a6e0971dbde0f04b6dd3bfab97ad5cdb7">More...</a><br /></td></tr>
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<tr class="memitem:a680f5368d5a13ff605466ab6a3d881bd"><td class="memItemLeft" align="right" valign="top">int&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="structMQTTAsync__message.html#a680f5368d5a13ff605466ab6a3d881bd">retained</a></td></tr>
<tr class="memdesc:a680f5368d5a13ff605466ab6a3d881bd"><td class="mdescLeft">&#160;</td><td class="mdescRight">The retained flag serves two purposes depending on whether the message it is associated with is being published or received. <a href="structMQTTAsync__message.html#a680f5368d5a13ff605466ab6a3d881bd">More...</a><br /></td></tr>
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<tr class="memdesc:aa9da73253863089ee90033c7f0dd28bf"><td class="mdescLeft">&#160;</td><td class="mdescRight">The dup flag indicates whether or not this message is a duplicate. <a href="structMQTTAsync__message.html#aa9da73253863089ee90033c7f0dd28bf">More...</a><br /></td></tr>
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<tr class="memitem:a2c8572ec595842768848982321835bfe"><td class="memItemLeft" align="right" valign="top">int&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="structMQTTAsync__message.html#a2c8572ec595842768848982321835bfe">msgid</a></td></tr>
<tr class="memdesc:a2c8572ec595842768848982321835bfe"><td class="mdescLeft">&#160;</td><td class="mdescRight">The message identifier is reserved for internal use by the MQTT client and server. <a href="structMQTTAsync__message.html#a2c8572ec595842768848982321835bfe">More...</a><br /></td></tr>
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<a class="el" href="structMQTTProperties.html">MQTTProperties</a>&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="structMQTTAsync__message.html#a48ff43122b16a12b6b8a9890ebfb6410">properties</a></td></tr>
<tr class="memdesc:a48ff43122b16a12b6b8a9890ebfb6410"><td class="mdescLeft">&#160;</td><td class="mdescRight">The MQTT V5 properties associated with the message. <br /></td></tr>
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<a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2>
<div class="textblock"><p>A structure representing the payload and attributes of an MQTT message. </p>
<p>The message topic is not part of this structure (see MQTTAsync_publishMessage(), MQTTAsync_publish(), MQTTAsync_receive(), MQTTAsync_freeMessage() and MQTTAsync_messageArrived()). </p>
</div><h2 class="groupheader">Field Documentation</h2>
<a id="aa9da73253863089ee90033c7f0dd28bf"></a>
<h2 class="memtitle"><span class="permalink"><a href="#aa9da73253863089ee90033c7f0dd28bf">&#9670;&nbsp;</a></span>dup</h2>
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<p>The dup flag indicates whether or not this message is a duplicate. </p>
<p>It is only meaningful when receiving QoS1 messages. When true, the client application should take appropriate action to deal with the duplicate message. This is an output parameter only. </p>
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<h2 class="memtitle"><span class="permalink"><a href="#a2c8572ec595842768848982321835bfe">&#9670;&nbsp;</a></span>msgid</h2>
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<p>The message identifier is reserved for internal use by the MQTT client and server. </p>
<p>It is an output parameter only - writing to it will serve no purpose. It contains the MQTT message id of an incoming publish message. </p>
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<h2 class="memtitle"><span class="permalink"><a href="#a6e0971dbde0f04b6dd3bfab97ad5cdb7">&#9670;&nbsp;</a></span>qos</h2>
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<p>The quality of service (QoS) assigned to the message. </p>
<p>There are three levels of QoS: </p><dl>
<dt><b>QoS0</b> </dt>
<dd>Fire and forget - the message may not be delivered </dd>
<dt><b>QoS1</b> </dt>
<dd>At least once - the message will be delivered, but may be delivered more than once in some circumstances. </dd>
<dt><b>QoS2</b> </dt>
<dd>Once and one only - the message will be delivered exactly once. </dd>
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<p>The retained flag serves two purposes depending on whether the message it is associated with is being published or received. </p>
<p><b>retained = true</b><br />
For messages being published, a true setting indicates that the MQTT server should retain a copy of the message. The message will then be transmitted to new subscribers to a topic that matches the message topic. For subscribers registering a new subscription, the flag being true indicates that the received message is not a new one, but one that has been retained by the MQTT server.</p>
<p><b>retained = false</b> <br />
For publishers, this indicates that this message should not be retained by the MQTT server. For subscribers, a false setting indicates this is a normal message, received as a result of it being published to the server. </p>
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<td class="memname">char MQTTAsync_message::struct_id[4]</td>
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<p>The eyecatcher for this structure. </p>
<p>must be MQTM. </p>
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<h2 class="memtitle"><span class="permalink"><a href="#af79efdfc9a4e082cbbafaed8fd333ce1">&#9670;&nbsp;</a></span>struct_version</h2>
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<p>The version number of this structure. </p>
<p>Must be 0 or 1. 0 indicates no message properties </p>
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<hr/>The documentation for this struct was generated from the following file:<ul>
<li>MQTTAsync.h</li>
</ul>
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