Re: howto: 2 users interactively edit the same file ?

[Pascal Bourguignon <spam@mouse-potato.com>]

Tim X <timx@spamto.devnul.com> writes:
> OK, I'm quite willing to accept all of that, though I'd still have
> concerns about how performance would be. If I understand you
> corrrectly, wouldn't there be a high likelihood of one input source
> "hogging" things - effectively causing a sort of starvation for the
> other user? There doesn't seem to be any sense of "fair" access in the
> model your describing and I still feel this would be problematic.

Indeed.  What's more, emacs imposes a "mutex" on the mini-buffer.  If
you type M-x in one frame, you cannot do anything else on the other
frame before you cancel the M-x or complete a command.


> I also wonder how emacs will handle things like local variables when
> you have two different users editing in the same buffer. Wouldn't this
> have consequences for things like point and region related commands?

point and region are frame local, not buffer local.


> I guess I'm over stating the complexities or something as the weight
> of opinion is against me. I have no problem with that, but my past
> experiences working on systems which have a similar model of operation
> where two users are affecting the same resource concurrently tells me
> its not as simple as just opening a second window on another display
> and everything else will just sort of magically work - I guess its my
> gut telling me there is a lot more too it and its a lot more complex -
> no real specific proof of this though.

Since there's no multithreading, there's no problem of accessing the
same resources concurrently.  It works exactly the same way with frame
on different display and several pointers & keyboards on different
displays than with several pointers & keyboards on the _same_ display,
or even one pointer & keyboard on one display with several frames: you
cannot type a key into two frames at the same "time": it'd produce two
distinct and ordered events and they're processed one after the other,
so there's no problem.

-- 
__Pascal Bourguignon__                     http://www.informatimago.com/
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