The Lotus Expeditor install image provides the C Client in two files.
Select the appropriate one for the platform on which the client will run.
- /MicroBroker Clients/c_client_win32.zip
- /MicroBroker Clients/c_client_linux_x86.zip
Each file contains the client libraries as well as full API documentation.
The MQTT v3 client provides publish and subscribe capabilities to topic destinations only.
Sending Messages: XPD621
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 will respond 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”.
Receiving messages: XPD621
There are two main ways of receiving messages using the API. Applications may either call the receive
function or set the messageArrived
String handling: XPD621
This section describes the details for sting handling.
Memory management: XPD621
This section provides information on memory management.
Persistence for messaging: XPD621
The client has a built-in persistence mechanism to ensure reliable messaging for the quality of service (QoS) in use. That means that messages published by the client at QoS 1 and QoS 2 are persisted until the client receives the acknowledgement from the server that the delivery completed successfully.
Example usage of the C API: XPD621
The C client supports MQTT v3 publish/subscribe messaging. The following examples illustrate use of the C API.
Parent topic: Developing an application using the MQTT proprietary API