SD16 nRF52840 - Queue library

Question

Hi everyone, 
 I am experimenting with the queue library 
 typedef struct
{
 int16_t records[16];
} my_sensor_data_t;

my_sensor_data_t my_sensor_data;

NRF_QUEUE_DEF(my_sensor_data_t, m_sensor_data_queue, 200, NRF_QUEUE_MODE_OVERFLOW);

void my_sensors_buffer() {

 ret_code_t err_code;
 my_sensor_data.records[0] = 1;
 my_sensor_data.records[1] = 2;
 my_sensor_data.records[2] = 3;
 my_sensor_data.records[3] = 4;
 my_sensor_data.records[4] = 5;
 my_sensor_data.records[5] = 6;
 err_code = nrf_queue_push(&m_sensor_data_queue, &my_sensor_data); // buffer some data
 APP_ERROR_CHECK(err_code);


} 
 After pushing some data by calling nrf_queue_push how do I print the data stored in the buffer?

tesc · Accepted Answer

Hi, 
 What you actually push and pop is one element; the first value in the arrays, which has the value 0. 
 You can use two approaches: 
 Either use your old approach with the my_sensor_data_t, have a queue with elements of that type, and use pointers to that type for pushing and popping to/from the queue... 
 ...or use your new approach with single elements in the queue, but then you have to manually loop through the records_push and records_pop arrays, and push/pop each element. 
 The confusion is probably coming from the queue handling API using pointers, combined with the fact that c arrays are stored as pointers as well. This means a funciton taking a pointer as argument can also take an array as argument, but that is only because an array in essence is a pointer to its first element. The result of passing an array to such a function is that the function operates on the first element of the array only, and it only works because the full array and the first element both have the same address and are of compatible types. 
 Regards, Terje

SD16 nRF52840 - Queue library

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