start mqtt client (based on paho.mqtt.c), basically works

3rd/paho.mqtt.c/src/MQTTSubscribeOpts.h

@@ -0,0 +1,46 @@
+/*******************************************************************************
+ * Copyright (c) 2018 IBM Corp.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v2.0
+ * and Eclipse Distribution License v1.0 which accompany this distribution.
+ *
+ * The Eclipse Public License is available at
+ *    https://www.eclipse.org/legal/epl-2.0/
+ * and the Eclipse Distribution License is available at
+ *   http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * Contributors:
+ *    Ian Craggs - initial API and implementation and/or initial documentation
+ *******************************************************************************/
+
+#if !defined(SUBOPTS_H)
+#define SUBOPTS_H
+
+/** The MQTT V5 subscribe options, apart from QoS which existed before V5. */
+typedef struct MQTTSubscribe_options
+{
+	/** The eyecatcher for this structure. Must be MQSO. */
+	char struct_id[4];
+	/** The version number of this structure.  Must be 0.
+	 */
+	int struct_version;
+	/** To not receive our own publications, set to 1.
+	 *  0 is the original MQTT behaviour - all messages matching the subscription are received.
+	 */
+	unsigned char noLocal;
+	/** To keep the retain flag as on the original publish message, set to 1.
+	 *  If 0, defaults to the original MQTT behaviour where the retain flag is only set on
+	 *  publications sent by a broker if in response to a subscribe request.
+	 */
+	unsigned char retainAsPublished;
+	/** 0 - send retained messages at the time of the subscribe (original MQTT behaviour)
+	 *  1 - send retained messages on subscribe only if the subscription is new
+	 *  2 - do not send retained messages at all
+	 */
+	unsigned char retainHandling;
+} MQTTSubscribe_options;
+
+#define MQTTSubscribe_options_initializer { {'M', 'Q', 'S', 'O'}, 0, 0, 0, 0 }
+
+#endif