From kde-core-devel  Thu Feb 28 20:06:00 2002
From: Waldo Bastian <bastian () kde ! org>
Date: Thu, 28 Feb 2002 20:06:00 +0000
To: kde-core-devel
Subject: Re: Bug#38142: wrong wallpaper list kills xlock (fwd)
X-MARC-Message: https://marc.info/?l=kde-core-devel&m=101492679323234

On Wednesday 27 February 2002 03:07 pm, David Faure wrote:
> On Tuesday 26 February 2002 10:36, Josef Weidendorfer wrote:
> > Hi,
> >
> > I don't know anything about the SaverEngine, but a good way to start
> > a daemon is to fork 2 times, and let the first fork exit. This way, t=
he
> > daemon gets init (PID 1) as parent, and has no connection to the orig
> > process.
>
> Thanks for the hint... but I don't see how to combine this with KProces=
s :(
> lockeng.cc uses a KProcess for the screensaver process, to be able to
> know when it exited (although... SaverEngine::hackExited() doesn't make
> much sense to me). .. and also to be able to terminate the screensaver =
by
> force (stopSaver(), calls stopHack()). Not sure how to do all of this w=
ith
> 2 forks. Waldo, you're the expert about such stuff, aren't you ?  /me
> trying flattery ;)

You will have to communicate the PID back to the parent process somehow. =
I=20
don't know if you will still get the SIGCHLD though. I doubt it. If you k=
eep=20
a pipe open with the daemon, the daemon will be able to tell you its PID,=
 so=20
that you can kill it. And you will be able to detect that the daemon died=
=20
because you can detect when the pipe closes.

Cheers,
Waldo

--=20
Advanced technology only happens when people take a basic idea and add to=
 it.
 -- Bob Bemer