Re: nanosleep & sginap

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Brian Furtaw (brian++at++dingbat.clubfed.sgi.com)
Thu, 1 Apr 1999 14:34:08 -0500

You actually want signals to awaken sleeping processes so control can be
transfered to the signal handler. Else you would miss the delivery of signals
like SIGTERM which is generated by ^C or the kill command, you would not want
that would you? So to get control of run away processes you actually want
sginap to awaken from signals. As Phil stated you don't need to worry about
signals interrupting your draw process unless of course you need to kill it.
You can read about signals on the signal man page.

Brian

On Apr 1, 9:47am, Phil Keslin wrote:
> Subject: Re: nanosleep & sginap
> Mattias.Johansson++at++saab.se wrote:
> >
> > Somebody forgot to update the manuals... or tell me about it, though :-)
> > >From the manual:
> >
> > Note that if the calling thread is interrupted by a signal before the
> > specified number of ticks has elapsed, sginap will return
> > prematurely.
>
> This is still true (and I believe true for some sleeps as well).
> Although it is possible for the sginap to awaken due to a signal, there
> are no signals delivered to the DRAW process that would have this
> effect. Even if it did, the wakeup would be effective only if it occured
> in the frame just prior to the vertical retrace in which the swapbuffers
> should happen. If it doesn't, then the DRAW will simply call sginap
> again.
>
> - Phil
> --
> Phil Keslin <philk++at++engr.sgi.com>
> -----------------------------------------------------------------------
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>-- End of excerpt from Phil Keslin

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