I have the code of a sensor in keil. I couldnt understand this piece of the code, what is it trying to do with errors? How can I learn the meanings of codes?

[mert]

[Petter Myhre]

---

 * @retval ::NRF_ERROR_INVALID_PARAM Invalid parameter(s) supplied.
 * @retval ::BLE_ERROR_INVALID_ATTR_HANDLE Invalid attribute handle(s) supplied, handles must be in the range populated by the application.
 * @retval ::NRF_ERROR_BUSY Procedure already in progress.
 * @retval ::BLE_ERROR_GATTS_SYS_ATTR_MISSING System attributes missing, use @ref sd_ble_gatts_sys_attr_set to set them to a known value.
 */
SVCALL(SD_BLE_GATTS_SERVICE_CHANGED, uint32_t, sd_ble_gatts_service_changed(uint16_t conn_handle, uint16_t start_handle, uint16_t end_handle));