Time measurement

[Shmuel Zeigerman <shmuz@...>]

I have an interactive Lua script that prompts user with a question and 
waits for an answer string from the standard input. The script measures 
the time it takes user to enter the answer, and the measurement should 
have 100 ms accuracy (or better).

Under Windows, it's achieved trivially by calling os.clock twice and 
subtracting the first value from the second. However, under Linux, the 
function returns 0 both times.

The questions:

1. How can I get time intervals of waiting for keyboard input measured 
with the 100 ms accuracy under Linux?

2. Is there a Lua solution to this problem that is portable between (at 
least) Linux and Windows?

Thanks.
--
Shmuel