paho.mqtt.c使用的总结_paho.mqtt.cpp 手册

1 MQTTAsync_connectOptions中的onSuccess和onFailure

1.1 onSuccess

只有在新建连接成功的时候在会执行这个函数，重连过程不管是否成功都不会执行这个函数。但是通过MQTTAsync_setConnected();接口设置的回调函数，无论是由于什么情况进行了连接，都会执行这个函数。

 1.2 onFailure

  无论是新建连接，还是重连，只要要连接失败，都会调用调用这个函数

	MQTTAsync_connectOptions connect_options = MQTTAsync_connectOptions_initializer;
 
	connect_options.cleansession = 1;
	connect_options.keepAliveInterval = 10;
	connect_options.connectTimeout = 10;
 
	connect_options.automaticReconnect = 1;
	connect_options.minRetryInterval = 1;
	connect_options.maxRetryInterval = 30;
 
	/*
	 * 只有新建连接才会执行这个函数,重连不会执行
	 */
	connect_options.onSuccess = connect_options_success;
 
	/*
	 * 如果无论是重连,还是连接失败都会调用这个函数
	 */
	connect_options.onFailure = connect_options_failure;
	connect_options.context = handle;
 
	ret = MQTTAsync_connect(handle, &connect_options);
	LOG_I(async, 0, "MQTTAsync_connect: %d\n", ret);