Sensoray 2224 Windows - Manual (Page 84)

kbhit
This routine senses whether the user presses a key on the keyboard. It can be used to break out of
infinite loops.
hexpr
This routine, written in Tcl itself, calls the Tcl expr functionand returns the result in hexidecimal prefixed
with “0x”. This result can then be used as a number in further computations.
84