Re: How to get DISPLAY of emacsclient?

[Max Nikulin <manikulin@gmail.com>]

On 25/11/2022 23:57, Stefan Monnier wrote:
>> Unfortunately the value of following expression is the DISPLAY environment
>> of the server process
>>
>>      emacsclient --eval '(getenv "DISPLAY")'
> 
> There are different ways which will give you different answers in
> different cases:
> 
> - you can check the `display` parameter of the selected frame (should
>    handle the `emacsclient --display` case).

     emacsclient --display "$DISPLAY" \
         --eval "(frame-parameter (selected-frame) 'display)"

may be a workaround, thank you for the idea. A caveat is that --display 
parameter becomes mandatory, DISPLAY environment is not enough:

     emacsclient --eval "(frame-parameter (selected-frame) 'display)"
     nil

Emacs daemon may have no x frames yet at the moment of emacsclient 
invocation.

> - you can check the `environment` parameter of the selected frame
>    (probably not very useful).

      emacsclient --display :0 \
           --eval "(frame-parameter (selected-frame) 'environment)"
      nil

> - You can check the `env` parameter (with `process-get`) of the proc
>    object that represents (on Emacs's side) the emacsclient connection.
>    For that you'll need to get access to this proc object, but I don't
>    know offhand how to.

I am unsure that -display argument is added to the `env` parameter. I do 
not like the following approach since I am afraid of races. Anyway it 
does not work

      emacsclient --eval "(process-get (car server-clients) 'env)"

So I have no idea how to access `proc` passed to a process filter as well.

Though it does not answer to the question how to get DISPLAY, the 
following is at least a workaround:

       DISPLAY= emacs -q --daemon
       emacsclient --display "$DISPLAY" \
           --eval "(require 'org)" \
           --eval "(org-get-x-clipboard 'PRIMARY)"