RE: FIFO and Dereferencing struct

mej7000 — Sat, 01 Jun 2024 12:26:50 GMT

Thanks! I probably copied the consumer print from my serial window out of order.

I made progress and got the output I expected. And, I get both the queue has member and queue is empty messages. Thanks for your reply!

void producer_thread(Device_t *_mygate)
{
    /* create data item to send */
    struct data_item_t *buf = k_malloc(sizeof(struct data_item_t));
    if (buf == NULL){
        LOG_INF("Unable to locate memory from the heap");
        return ;
    }

    /* Populate the data item. This is usually done using memcpy() */
    memcpy(&buf->MYGATE, _mygate, sizeof(*_mygate));

    LOG_INF("dcheck: producer thread: cmd: %d uuid: %s d0: %d", buf->MYGATE.cmd, buf->MYGATE.uuid, buf->MYGATE.d0);

    /* send data to consumers */
    int err = k_fifo_alloc_put(&my_fifo, buf);
    if(err){
        LOG_ERR("ERROR, fifo alloc put failed: %d", err);
    }

    // k_free(buf); data access violation
}

void consumer_thread()
{
    struct data_item_t  *rx_data;

    if(k_fifo_is_empty(&my_fifo)){
        LOG_ERR("FIFO1 Queue is Empty");
    }
    else{
        LOG_DBG("FIFO1 Queue has member");
    }
    
    rx_data = k_fifo_get(&my_fifo, K_NO_WAIT);

    /* process FIFO data item */
    Device_t temp = rx_data->MYGATE;

    LOG_INF("dcheck: consumer thread: cmd: %d uuid: %s d0: %d", temp.cmd, temp.uuid, rx_data->MYGATE.d0);

    k_free(rx_data);

    /*
        Returns Non-zero if the FIFO queue is empty.
        Returns 0 if data is available.
    */

    if(k_fifo_is_empty(&my_fifo)){
        LOG_ERR("FIFO2 Queue is Empty\n");
        k_sleep(K_MSEC(100));
        return;
    }
}

RE: FIFO and Dereferencing struct

Turbo J — Sat, 01 Jun 2024 06:58:33 GMT

The if() statement around the k_fifo_empty() call has its logic inversed. Check the rx_data pointer directly, it should be NULL with your code.

The other clue would be that the consumer prints out before the producer, which is obviously wrong. Look at the time stamps in logs above.