About Queue library (SDK 17.1.0)

[June6]

Hi, Nordic

Recently, I'm experimenting with the queue library.

I found some strange problems:

1. When the data types of my data structure members are not unique, using queue will cause the whole system to crash without even error codes

typedef struct {
  bool flag;
  uint8_t data1;
  uint32_t data2;
  uint8_t data3;
  uint8_t data4;
  uint8_t data5;
  uint8_t data6;
} data_t;

NRF_QUEUE_DEF(data_t, m_data_queue, 255*sizeof(data_t), NRF_QUEUE_MODE_NO_OVERFLOW);

data_t test_data;

test_data.flag = true;
test_data.data1 = 0x01;
test_data.data2 = 0xAABBCC;
test_data.data3 = 0x03;
test_data.data4 = 0x04;
test_data.data5 = 0x05;
test_data.data6 = 0x06;

ret = nrf_queue_write(&m_data_queue, &test_data, sizeof(test_data));
APP_ERROR_CHECK(err_code);

data_t data_read;

ret = nrf_queue_read(&m_data_queue, &data_read, sizeof(data_read));
APP_ERROR_CHECK(err_code);

The whole system crashed before the program even performed error checking for queue writes

2. So I modified it according to other examples, as follows

typedef struct {
 uint8_t data[9];
} data_t;

NRF_QUEUE_DEF(uint8_t, m_data_queue, 255*sizeof(data_t), NRF_QUEUE_MODE_NO_OVERFLOW);

data_t test_data;

test_data.data[0] = true;
test_data.data[1] = 0x01;
test_data.data[2] = 0xAA
test_data.data[3] = 0xBB;
test_data.data[4] = 0xCC;
test_data.data[5] = 0x03;
test_data.data[6] = 0x04;
test_data.data[7] = 0x05;
test_data.data[8] = 0x06;

ret = nrf_queue_write(&m_data_queue, &test_data.data, sizeof(test_data));
APP_ERROR_CHECK(err_code);

data_t data_read;

ret = nrf_queue_read(&m_data_queue, &data_read.data, sizeof(data_read));
APP_ERROR_CHECK(err_code);

My questions are as follows:

In 1, do I have any misunderstandings? If so, please point it out!!!

In 2, can I change the data type in NRF_QUEUE_DEF from uint8_t to data_t？

In 2, I have 255 groups of data. What should I do if I want to take the 3rd to 5th bytes (0xaabbcc) in each group of data as a condition for overwriting the data content of the queue? Is it necessary to perform queue reading to read all the contents in the queue, open up a space to compare each group of data, and then write all the updated contents to the queue again? Is there a more elegant way, such as specifying the write location of the queue or other ways?

Regards,

June6

[June6]

In addition, I have seen in another ticket that it is recommended to use push instead of write in overwrite mode. This ticket will not tangle with this problem.

[June6]

Besides, my mother tongue is not English. Please forgive me for any strange expression.

[Jared]

Hi there,

Is the issue mitigated If you set data2 type to uint8_t instead of uint32_t?

regards

Jared

[June6]

No, it hasn't improved.

Moreover, I found that as long as the data type parameters filled in NRF_QUEUE_DEF are user-defined structures, the number of members of that structure cannot be too many.

Specifically, I tested in the second test segment. If the array in data_t is defined as data [7] or larger, there will be a problem.

On the contrary, if the data type filled in NRF_QUEUE_DEF is uint8_ t. Then no matter how many members of the structure are, there is no problem.

This phenomenon is very strange. It is reasonable to say that although the parameter passed into the actual operation function is a pointer, the space occupied by my structure members is a fixed size, so I don't need to apply for additional memory. I can't figure it out

[Jared]

Hi there,

It seems that the wrong parameter is passed to nrf_queue_write() and nrf_queue_read() in the first case. The third parameter should be the element count, not the size of the struct. Try replacing it with 1.

regards

Jared