Hä?! A clock shows the period of time we are currently in. A clock only showing hours would for example indicate that we are in the 14th hour of the day, for the entire duration of that hour. That is not an error. Similarly, a hh:mm clock will show the hour and minute we are currently in for the duration of that minute.
No clock can display the exact current moment of time. That would require infinite digits, and even then those will be late, since lightspeed will ensure you recieve the femtoseconds and below really late.
No clock can display the exact current moment of time. That would require infinite digits, and even then those will be late, since lightspeed will ensure you recieve the femtoseconds and below really late.