+SR_PRIV unsigned char *lascar_get_config(libusb_device_handle *dev_hdl);
+SR_PRIV int lascar_el_usb_handle_events(int fd, int revents, void *cb_data);
+SR_PRIV void lascar_el_usb_receive_transfer(struct libusb_transfer *transfer);
+SR_PRIV int hw_dev_acquisition_stop(struct sr_dev_inst *sdi, void *cb_data);