® Expeditor install image provides the C Client in two files.
Select the appropriate one for the platform on which the client is to run.
- /MicroBroker Clients/c_client_win32.zip
- /MicroBroker Clients/c_client_linux_x86.zip
Each file contains the client libraries and the full API documentation.
The MQTT v3 client provides publish and subscribe capabilities to topic destinations only.
Sending messagesParent topic: Developing an application using the MQTT API
When using quality of service (QoS) 0, the publish function does not receive a response from the server ("fire and forget"). For the more reliable QoS levels 1 and 2, the server responds, but the publish call does not wait for the response; it returns control to the application as soon as the publish request is successfully sent. After publish returns, and before the complete publish response has been received from the server, a message is said to be "in-flight."
There are two main ways of receiving messages using the API. Applications can either call the receive
function or set the messageArrived
This section describes the details for sting handling.
This section provides information on memory management.
The client has a built-in persistence mechanism to ensure reliable messaging for the quality of service (QoS) in use. That approach means that messages published by the client at QoS 1 and QoS 2 are persisted until the client receives the acknowledgment from the server that the delivery completed successfully.
Example usage of the C API
The C client supports MQTT v3 publish and subscribe messaging. The following examples illustrate use of the C API.