Why doesn't Emacs have an `active-timer-p' command, or why can't I find it?

[Alan Mackenzie]

Hello, Emacs.

There doesn't appear to be an easy way in a Lisp program to determine if
a timer object is active.  Something like (active-timer-p TIMER), or
even (timerp TIMER t), where the t is an &optional argument meaning
"active" (a bit like the LIVE parameter in minibufferp).

Does such a function really not exist, or have I somehow not managed to
find it?

If it doesn't exist, what is the reason?  The command timer-list clearly
manages to know this.  The usefulness of active-timer-p is surely
obvious.  (Well, it is to me, at least.)

At the very least, there could be a section in the Elisp manual
documenting why the function doesn't exist.

-- 
Alan Mackenzie (Nuremberg, Germany).