Re: How to detect two emacs process in Elisp code?

[stardiviner]

Emanuel Berg via Users list for the GNU Emacs text editor 
<help-gnu-emacs@gnu.org> writes:

> Eli Zaretskii wrote:
>
>>> (let ((emacs-processes
>>>        (length (mapcar
>>>                 'string-to-number
>>>                 (seq-filter
>>>                  (lambda (str)
>>>                    (not (string-empty-p str)))
>>>                  (split-string
>>>                   ;; (shell-command-to-string "ps -C emacs -o pid=")
>>>                   (shell-command-to-string "ps -C emacs -o pid=")
>>>                   "\n"))))))
>>>   (when (<= emacs-processes 1)
>>>     (message "init-emacs-session loading")
>>>     (require 'init-emacs-session)))
>>
>> Why do you need to use an external command ('ps')?
>> What's wrong with using list-system-processes and
>> process-attributes instead?
>
> Uhm... like this:
>
> (defun count-emacs ()
>   (let ((eps 0))
>     (cl-loop for pid in (list-system-processes)
>              when (string= (cdar (process-attributes pid)) "emacs")
>              do (cl-incf eps) )
>     eps) )
> ;; (count-emacs) ; 1
>
> ?

This does not work perfectly, when I have Emacs running, then start "emacs -q"
from new command. The upper `(list-system-processes)` solution get result "1"
instead of "2". Maybe somewhere is wrong?

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