State object

SMF uses a data structure of type struct smf_ctx to track the current state of the state machine. This structure is embedded within a larger structure called the state object that holds the following:

• SMF's context structure.
• The zbus channel of the latest message received.
• The contents of the latest message received.
• Any extended state variables needed by the module.

For example, the FOTA module defines its state object structure:

struct fota_state_object {
    /* This must be first */
    struct smf_ctx ctx;

    /* Last channel type that a message was received on */
    const struct zbus_channel *chan;

    /* Buffer for last zbus message */
    uint8_t msg_buf[MAX_MSG_SIZE];

    /* Extended state variable: nRF Cloud FOTA poll context */
    struct nrf_cloud_fota_poll_ctx fota_ctx;
};

The structure is allocated in the module's thread and passed to all SMF functions.