[m-users.] Two more predicates for dealing wih threads

[Volker Wysk]

Hi.

Yes, you do have to always treat the answer as out of date. And include a
big warning sign in the documentation. Of course the result won't say
"something about the state of the world NOW". 

I haven't thought about that, when I wrote my message to this list. But it
still could be useful to have those predicates. Sometimes an answer, that's
(a little) outdated, can still be useful. It depends on the case. 

In my case, I wanted to better understand what's going on. If I have a bug
or not. So it was intended for debugging messages.

Cheers,
Volker

Am Montag, dem 06.11.2023 um 02:17 +1300 schrieb Richard O'Keefe:
> What do these operations actually mean?
> When you get an answer from operations like these,
> you always have to treat that answer as out of date.
> I had a time-of-check/time-of-use bug recently.
> It was one of those "check if something exists,
> allocate workspace, try to use it" bugs.  The kind
> where you go "but that's IMPOSSIBLE.  The code
> just *checked* that this thing existed, how could it
> not exist, oh wait, this is concurrent...
> 
> Is there any way to formulate these things so that
> when a thread looks at the result, it tells the thread
> something about the state of the world NOW?
> 
> On Sun, 5 Nov 2023 at 23:28, Volker Wysk <post at volker-wysk.de> wrote:
> > 
> > Hi!
> > 
> > I'm playing with threads, and in order to better see what's going on,
> > I'd like to have two more predicates:
> > 
> > - One for thread.channel, which returns the current length of the channel.
> > - One for thread.semaphore, which returns the current value of the
> >   semaphore.
> > 
> > It would be nice, if those could be added.  :)
> > 
> > 
> > Cheers,
> > Volker
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