\DOC start_time

\TYPE {start_time : unit -> Timer.cpu_timer}

\SYNOPSIS
Set a timer running.

\KEYWORDS
time.

\DESCRIBE
An application {start_time ()} creates a timer and starts it. A later
invocation {end_time t}, where {t} is a timer, will need to be called
to get the elapsed time between the two function calls.

\FAILURE
Never fails.

\EXAMPLE
{
- val clock = start_time ();
> val clock = <cpu_timer> : cpu_timer
}


\COMMENTS
Multiple timers may be started without any interfering with the others.

Further operations associated with the type {cpu_timer} may be found
in the Standard ML Basis Library structures {Timer} and {Time}.

\SEEALSO
Lib.end_time, Lib.time.
\ENDDOC