Re: catch logout/SIGHUP

[Jochen Baier <Jochen Baier stud uni-karlsruhe de>]

Ben Johnson wrote:

> On Thu, Jul 21, 2005 at 03:39:46AM +0200, Jochen Baier wrote:
>  
>
> > hi,
> >
> > i wonder what is the right procedure to do some cleanup if the user 
> > logout from session
> > and the program is still alive. ("Save file before exit" etc)
> >
> > I thought "system (SIGHUP,...)" is the right way, but i didnt find this 
> > function in code from gedit, anjuta etc.. so what is  the right way to 
> > do this ?
> >    
>
> as far as I know glib and gdk/gtk haven't added any support for signal
> handling, so I imagine using sigaction() and associated POSIX functions
> are what you'd want to use.  (what is this system(SIGHUP,...) of which
> you speak?  never heard of it.)
>  
sorry should be called: signal(....)

> the only thing I'm aware of that needs to be said about signal handling
> in relation to gtk is about dealing with asynchronous nature of signals.
> gtk assumes it knows everything about what threads are running.  if you
> start executing gtk code during a signal handler, you run the (very
> probable) risk of making gtk stomp on itself when your handler runs on
> top of what gtk thinks is a thread-autonomous operation.
>
> I'm not sure exactly what mechanism to use...  but the best way to
> handle signals is to make the actual signal handler do something very
> simple and non-gtk-interactive/invasive like setting some kind of simple
> flag -- THEN engineer some way for the gtk main loop to respond to that
> flag being set.  make sense?
>  
if found something interesting about it:

http://wwwtcs.inf.tu-dresden.de/~tews/Gtk/x2991.html

i also found out how gedit etc handle this:

they connect to "save_yourself" ( WM_SAVE_YOURSELF) as part of session 
management.

well, thanx anyway Jochen