Re: Win32 signals code, take two

> Magnus Hagander wrote:
> > Here's an updated version of the proposed win32 signals
> code, with the
> > following main changes:
>
> One small possible revision to consider:  As I read the code,
> all manipulation to pg_signal_queue is inside a
> CriticalSection, and it is only set (> 0) when there are
> pending signals.
>
> ISTM that pg_queue_signal can abort without calling
> QueueUserAPC pg_signal_queue is already set.  This will keep
> the dispatch function from getting called extra times.
> Paranoia statement
>
> pg_signal_queue = 0;
>
> could possibly be added at the end of the dispatch.

No, I don't think it can't. Consider delayed signals. When leaving the
dispatch function, pg_signal_queue may very well be != 0. Only
(pg_signal_queue & ~pg_signal_mask) should be zero.

Also, I think it's best if the mask is checked upon signal *delivery*,
not queueing. The signal could be blocked when delivered and non-blocked
on delivery. If we never queue a APC in this case, the signal will be
lost. But we *could* do the check in pg_signal_queue, but then against
(pg_signal_queue &~ pg_signal_mask).

//Magnus