Re: filenotify.el

[Michael Albinus <michael.albinus@gmx.de>]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> Just to be sure. The different low-level packages are not fully
>> compatible (event names differ, for example); it would be a nightmare
>> for filenotify.el when the different packages compete under the hood.
>
> Why would they compete?  In the unlikely case that both gfilenotify and
> inotify are provided, can't the code just use one of the two without
> being impacted by the other?  If not, why not?  Can we fix it so as to
> avoid such conflicts?

[...]

> Agreed, but the better option is to make sure they don't conflict with
> each other, and then make filenotify.el choose one of the available ones
> "arbitrarily".

Well, filenotify.el shall decide for one of the available low-level
packages, and use it. I'll change accordingly.

However, any Lisp package could still decide to activate "the other"
low-level file notification package if linked to Emacs. In this case, we
must ensure that the incoming file-notify events can be distinguished.

Such an event looks like (DESCRIPTOR ACTION FILE). Different low-level
packages must use unique DESCRIPTORs then. As of today, this is not
guaranteed; both gfilenotify and inotify use integers for example.

There's no urgency for this; as of today Emacs' configure decides for
one and only one package. And in Tramp I use already descriptors which
are unique for Tramp (it's the internal Tramp vector for the file to be
monitored).

>         Stefan

Best regards, Michael.