[Question] Having brains again after being headless?

David T. Lewis lewis at mail.msen.com
Fri Dec 6 16:52:25 UTC 2002


On Fri, Dec 06, 2002 at 02:50:16PM +0100, Ian Piumarta wrote:
> On Fri, 6 Dec 2002, Markus Gaelli wrote:
> > 
> > I wonder if and how it is possible to send a headless squeak-process a 
> > signal, to show its gui again?
> > Would be nice for swiki-administration.
> 
> What a fabulous idea.  Unless OSPP can easily handle this entirely within
> the image (Dave??) I'd be happy to add SIGUSR1->reconnectDisplay() to the
> Unix VM.


Yes, that's easy. In my development code, I've already added generalized
signal forwarding, such that you can request any unix signal to be
handled by signaling a Smalltalk semaphore. All you would need to do
is set up a Smalltalk process to wait on a semaphore and toggle the
capitation state (tm).


I've done the same thing with aio events also, which is a nice way to
let a Smalltalk process receive notification whenever data becomes
available on a pipe (or file, or socket...). This gives you asynchronous
"file events" similar to Tk/tcl.


The only small problem is that I have OSProcess and CommandShell all
ripped apart at the moment, and I won't have time to put it into a 
releasable state for several weeks. Sorry about that, I will get to it
as soon as I can though.


Stephen Pair replied separately concerning how to open and close the
display on a swiki using the existing OSProcess.


Dave




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