Re: Query about Emacs Process API | Asynchronous processes

[Eli Zaretskii <eliz@gnu.org>]

> From: Narendra Joshi <narendraj9@gmail.com>
> Date: Sun, 05 Jul 2020 00:42:22 +0200
> 
> #+begin_src emacs-lisp
> (make-process :name "a-pty-process" :command (list nil) :buffer "*a-pty-process-buffer*")
> #+end_src
> 
> This creates a process with a pseudo terminal. This process is shown by
> `list-processes`
> 
> #+begin_src 
>  Process ▼ PID Status Buffer TTY Thread Command 
> a-pty-process   -2      run     *a-pty-process-buffer*    /dev/pts/1   Main         
> #+end_src
> 
> ^ The process ID is a negative number. It makes me think that there is
> no real sub-process (OS level) yet. Is that true? If not, what is being
> executed by the sub-process?

From the ELisp manual:

     :command COMMAND
          Use COMMAND as the command line of the process.  The value
          should be a list starting with the program’s executable file
          name, followed by strings to give to the program as its
          arguments.  If the first element of the list is ‘nil’, Emacs
          opens a new pseudoterminal (pty) and associates its input and
          output with BUFFER, without actually running any program; the
          rest of the list elements are ignored in that case.