Re: persistent file locks

[Michael Heerdegen <michael_heerdegen@web.de>]

Eli Zaretskii <eliz@gnu.org> writes:

> > When the user runs multiple Emacs processes, my lib should not cause
> > both processes to append to one and the same file.  I want to use Emacs
> > file locks for preventing that.  After reading
> > (info "(elisp) File Locks"), it seems that locks are handled only
> > implicitly, and are removed when the associated buffer is not modified
> > any more.  I need a persistent lock.  Is there a way to achieve this?
> > Or what would you recommend to do instead?
>
> Name the file with the Emacs PID in the file name?

Thanks.  That would work, but it would mean that I would either
pollute some user's directory with lots of differently named log files,
or I would have to implement some merging/removing mechanism for those.

I would prefer a solution with a constant log file name (additional
Emacs processes would just avoid logging if the file is locked, or
alternatively log into a different file named emacs-log~2 or so).

Eli, does your answer imply that there are only workaround solutions,
i.e., that there is no clean way to avoid automatic lock removal by
Emacs?

Thanks,

Michael.