Re: possible to exchange server and client?

[pjb@informatimago.com (Pascal J. Bourguignon)]

anhnmncb <anhnmncb@gmail.com> writes:

> pjb@informatimago.com (Pascal J. Bourguignon) writes:
>
>> anhnmncb <anhnmncb@gmail.com> writes:
>>
>>> hmm, I want to run emacs with server-start in Xorg, then create a frame
>>> in console, then in the console frame, M-x server-start to make that
>>> frame become an emacs server too, so now I can safely exit the emacs
>>> running on xorg.
>>
>> This is where you are in error.  There is not one instance of emacs
>> per frame.  Frames are but windows open on the same emacs process.
>> You can make-frame and  delete-frame at will, but this is always the
>> same emacs process.  
>>
>> In addition, server-start is totally independant of what frames emacs
>> has currently open.
>> "Running emacs with server-start in Xorg" is meaningless a sentence.
>>
>> If you exit emacs from one frame, then all frames will be killed,
>> because there's only one emacs process.
>>
>> And if you delete the last frame, emacs will also be killed, that's
>> why I'd advise you to always keep at least one (unused) frame open, so
>> you can reconnect to your emacs process when you get disconnected from
>> your current frame/tty.
>
> Thanks for the patient and detailed explanation! Make me realise my
> totally wrong concept misled you.
>
> Let me give another try to express my need:
>
> I start an emacs process, then make a new frame, then let this new frame
> become a new emacs process, is it possible?

No, this is not possible.


There is one thing that would be possible, at the X11 level, but it
wouldn't be too interesting.  In X11, you can open a window inside
another window.  Some programs take a -windowid option to let you
choose which window they should be hosted in.

To see what I mean, try this:

export DISPLAY=:0.0
emacs & 
xv -windowid $(xwininfo -int  2> /dev/null |awk '/Window id/{print $4}') some-picture.jpg

and then, click on the emacs frame.  xv will display the picture
inside the emacs frame.

So we could imagine a patched emacs that would take a -windowid
option, and then you could launch a new emacs process that would use
an existing frame.  I don't know what X would do if the old process
was killed then, I guess it would kill the surrounding frame, since it
would still belong to the original process, along with the embedded
frame of the second process.


Perhaps the following solution would match your need.  Instead of
opening the frames directly in the native X server, you could run them
in a Xnest server.  Then you could launch another emacs process, open
a frame in the same Xnest server.  Both emacs frames would be
displayed inside the same Xnest window, but as independent Xnest
windows.  The next step would be to use xmove or vnc to move X windows
from one display to another, and manage sessions:

http://www.hermann-uwe.de/blog/how-to-hijack-an-already-running-x11-application-via-ssh-x

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

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