Re: Remote display-time-mail-file

[Stefan Monnier <monnier@IRO.UMontreal.CA>]

> Maybe I'm missing something, but I don't see how this can help.  For
> starters, time.el needs Tramp to check the remote every time, so the
> cache just gets in the way.

But each use from time.el might end up calling some internal Tramp
functions several times, so the cache may still speed things up.

> For other use-cases, I wonder how can the cache validity be limited in
> terms of time.  Files are modified by programs that access them, not
> because some amount of time has passed.

Indeed, but short of using some inotify-like thingy, Emacs has no way to
know when a file is modified by some other program, so the best it can
do is to say that it will be out of sync at worst up to N seconds.

> How will a Lisp program that accesses remote files know which number
> of seconds to set in this variable?  What am I missing?

In general, there is no good answer.  But clearly, your time.el case
will want to set this limit to just below to refresh rate.


        Stefan