Re: Add pselect, ppoll system calls.

[Michael Kerrisk]

David,

> On Fri, 2005-08-05 at 14:49 +0200, Michael Kerrisk wrote:
> > If I change your program to do something like the above, I also
> > do not see a message from the handler -- i.e., it is not being
> > called, and I'm pretty sure it should be.
> 
> Hm, yes. What happens is we come back out of the select() immediately
> because of the pending signal, but on the way back to userspace we put the
> old signal mask back... so by the time we check for it, there _is_ no
> (unblocked) signal pending. 
> 
> If it's mandatory that we actually call the signal handler, 

I'm just about to go off on holiday, and don't have a chance to pull up 
all the relevant standards details at them moment.  However, I'm fairly 
sure that the signal handler should be called.  (Try running a modified 
version of my program on Solaris 10 or the Unix-03 conversion of AIX 
(5.3?).)

> then we need to
> play tricks like sigsuspend() does to leave the old signal mask on the
> stack frame. That's a bit painful atm because do_signal is different
> between architectures. 

Yes, I'd say the behaviour should in fact be like what sigsuspend() does.

Cheers,

Michael
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