#include <dc1394/juju/firewire-cdev.h>
struct fw_cdev_get_cycle_timer - read cycle timer register : system time, in microseconds since the Epoch : isochronous cycle timer, as per OHCI 1.1 clause 5.13
The FW_CDEV_IOC_GET_CYCLE_TIMER ioctl reads the isochronous cycle timer and also the system clock. This allows to express the receive time of an isochronous packet as a system time with microsecond accuracy.