Re: [PATCH] poke: use pthread functions only if available

[Hannes Domani]

 Am Mittwoch, 21. Februar 2024 um 16:57:27 MEZ hat Hannes Domani via poke-devel 
<poke-devel@gnu.org> Folgendes geschrieben:

> Am Mittwoch, 21. Februar 2024 um 16:30:41 MEZ hat Jose E. Marchesi 
> <jemarch@gnu.org> Folgendes geschrieben:
>
> > >  Am Mittwoch, 21. Februar 2024 um 11:47:54 MEZ hat Jose E. Marchesi 
> > ><jemarch@gnu.org> Folgendes geschrieben:
> > >
> > >> Hi Hannes.
> > >>
> > >> Thanks for the patch.
> > >>
> > >> How does poke handle ctrl-C in the Windows terminal with this patch
> > >> applied?  Does it get back to the (poke) prompt or kills the process?
> > >
> > > If you press ctrl-c when no poke command is currently executing, nothing
> > > happens.
> > > If you press ctrl-c while a poke command is processing, it immediately 
> > > stops
> > > and goes back to the (poke) prompt (apparently pvm_handle_signal does 
> > > this).
> >
> > Yes, that covers when you press Ctrl-C while executing the PVM.  Like
> > for example if you do:
> >
> >   (poke) while (1) {}
> >   <Ctrl-c>
> >
> > On the other side, poke_sigint_handler is invoked when the PVM is not
> > executing, i.e. when Poke code is not running.  Like in:
> >
> >   (poke) type this then press ctrl-c^C
> >
> >   (poke) _
> >
> >
> > i.e. the signal handler removes the current text at the prompt and then
> > draws a prompt again.  I expect your patch to impact this second case.
>
> OK, so that's what this signal handling is for, you're right, this case
> doesn't work, nothing at all happens if you press ctrl-c in the prompt.
>
> I'll see if I can fix this.

So it's not possible to handle ctrl-c the same way on windows, since
the signal handler is always called in a new thread there.
Though I don't think that this should stop us from getting this in, most
people probably wouldn't even notice that this is missing (I didn't).

I'm just not completely sure if the check via #ifdef HAVE_PTHREAD_H is
fine, or if I should use #ifndef _WIN32, or something else, instead.


Hannes