Mail Archives: cygwin-developers/2001/04/18/20:22:23
----- Original Message -----
From: "Christopher Faylor" <cgf AT redhat DOT com>
To: <cygwin-developers AT cygwin DOT com>
Sent: Thursday, April 19, 2001 10:19 AM
Subject: Re: pthread condition vars - Doh!
> On Thu, Apr 19, 2001 at 10:05:55AM +1000, Robert Collins wrote:
> >----- Original Message -----
> >From: "Christopher Faylor" <cgf AT redhat DOT com>
> >To: <cygwin-developers AT cygwin DOT com>
> >Sent: Thursday, April 19, 2001 9:51 AM
> >Subject: Re: pthread condition vars - Doh!
> >
> >
> >> On Thu, Apr 19, 2001 at 09:46:52AM +1000, Robert Collins wrote:
> >> >I've just found out that SignalObjectAndWait, which I use in
several
> >> >locations in the pthreads code, is not available on 9x platforms.
> >> >SignalObjectAndWait is the appropriate function to prevent races
for
> >> >emulated posix objects that involve more than 1 win32 object.
> >>
> >> Yep. I have long wanted a SingalObjectAndWait for Cygwin's signal
> >> handling but I couldn't use it for this reason. I missed that you
> >> were using this in your new code.
> >>
> >> I assume that you'll be providing some kind of wrapper to handle
> >> this?
> >
> >Nice try :]. Long term I hope so. Short term if(95){race}else {don't
> >race}.
>
> I just meant that you'd provide a wrapper that did something like:
>
> signal_object_and_wait (blah)
> {
> DWORD res;
> if (os_being_run == winNT)
> res = SignalObjectAndWait (blah)
> else
> {
> SetEvent (or whatever);
> res = WaitForSingleObject ();
> }
>
> return res;
> }
Yeah, long term. I'm not going to create such a wrapper until the
problems solved for at least 2 different object combinations. Then I'll
look for common elements and see what arises.
> >Which given the win32 scheduler should pretty much guarantee no races
> >(particularly if the pri is above the available priority for any
other
> >cygwin threads), and as we are blocked, we won't deadlock. I've only
> >just started thinking about this - this is really verbal rambling..
>
> I came across a web site years ago that claimed to be able to do this
> in a non-raceable fashion -- or at least I dreamed I did. I never
have been
> able to find it again.
I'm happy to contribute money for hypnosis :]
Rob
> cgf
>
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