Re: browse-url

[Hugh Lawson <hlawson@triad.rr.com>]

David Kastrup <dak@gnu.org> writes:

> Hugh Lawson <hlawson@triad.rr.com> writes:
> 
> > David Kastrup <dak@gnu.org> writes:
> >
> >> Hugh Lawson <hlawson@triad.rr.com> writes:
> >> 
> >> > Debian sarge
> >> > Emacs 21.4.1
> >> >
> >> > browse-url works fine if firefox is already running. 
> >> >
> >> > But suppose firefox isn't running.
> >> >
> >> > If I do 'M-x browse-url' and fill in the url, then firefox pops up for
> >> > a second and then disappears.  The same thing happens with links I
> >> > click on in Emacs.
> >> >
> >> > I think I can imagine a shell script to deal with this, but surely
> >> > there is something alread in Emacs.
> >> 
> >> The definition of browse-url-generic in browse-url.el needs to get
> >> replaced with:
> >> 
> >> (defun browse-url-generic (url &optional new-window)
> >>   ;; new-window ignored
> >>   "Ask the WWW browser defined by `browse-url-generic-program' to load URL.
> >> Default to the URL around or before point.  A fresh copy of the
> >> browser is started up in a new process with possible additional arguments
> >> `browse-url-generic-args'.  This is appropriate for browsers which
> >> don't offer a form of remote control."
> >>   (interactive (browse-url-interactive-arg "URL: "))
> >>   (if (not browse-url-generic-program)
> >>     (error "No browser defined (`browse-url-generic-program')"))
> >>   (apply 'call-process browse-url-generic-program nil
> >> 	 0 nil
> >> 	 (append browse-url-generic-args (list url))))
> >
> >
> > I don't understand how this solves my problem.  If mozilla-firefox
> > is open and running. all is well. If it isn't then there is a
> > problem.
> 
> Emacs has several possibilities to start processes.  Starting with
> call-process and 0 as third argument detaches the process completely
> from Emacs.
> 
> Starting the process with start-process, in contrast, leaves the
> process associated with Emacs.  If the process detaches itself from
> the tty, Emacs assumes that it is finished and kills the process
> group.  This is what happens with new Firefoxes that try to escape the
> Emacs tty.
> 
> This is why you need an Elisp function that will use call-process
> instead of start-process for starting Firefox if it is supposed to
> survive detaching.

Thanks for the explanation, David.  I had trouble making it work, so
as a trial, I added the following two functions to my ~/.emacs file. 

Please critique. I did this purely empirically, with no real
understanding.



(defun browse-url-firefox (url &optional new-window )
  ;;new-window ignored
"Ask the firefox browser to  load URL."
 (apply 'call-process "firefox" nil
         0 nil (list url)))


(setq browse-url-browser-function  'browse-url-firefox)

-- 
Hugh Lawson
hlawson@triad.rr.com