finding process id of a window

[Jochen.Baier at stud.uni-karlsruhe.de]

Quoting Joel Dice <dicej at mailsnare.net>:

> On Tue, 29 Mar 2005, Norberto Bensa wrote:
> 
> > Joel Dice wrote:
> >> On Mon, 28 Mar 2005 Yossi.Itzkovich at ecitele.com wrote:
> >>> I have few  X applications, started from the command line with identical
> >>> command line, but each has a different DISPLAY environment variable.
> >>> Is there a way to get the process id of a process from its window ?
> >>
> >> I asked about this a few months ago, and apparently it's not possible.
> >> What do you need the process id for?  Perhaps what you're trying to do
> can
> >> be accomplished some other way.
> >
> > Maybe I'm a bit off-topic here, but perhaps you should take a look at
> xkill
> > code.
> 
> Good idea.  Unfortunately, xkill just calls XKillClient(Display,XID), 
> which does not give you access to the PID.

hi,

maybe this is what you looking for:


gint get_pid (Window w)
{
  
  Atom actual_type;
  int actual_format;
  unsigned long nitems, leftover;
  unsigned char *pid_return;
  gint pid=0;
  int status;
  gint err;

  Atom net_wm_pid=XInternAtom(GDK_DISPLAY(), "_NET_WM_PID", False);
    
  gdk_error_trap_push();
  
  status=XGetWindowProperty(GDK_DISPLAY(), w,
      net_wm_pid, 0,
      1, False, XA_CARDINAL, &actual_type,
      &actual_format, &nitems, &leftover, &pid_return);
  
  err=gdk_error_trap_pop();
    
  if (err!=0 || status != Success)
    return 0;
     
  if (pid_return) {
    pid=*(gint *) pid_return;
    XFree(pid_return);
  }

  return pid;
}


(not all windows have this property set)

regards jochen