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Date: Tue, 4 Mar 2025 11:08:49 +0100
To: cygwin@cygwin.com
Subject: Re: Cygwin 3.6: Supporting 128 POSIX realtime (SIGRTMAX-SIGRTMIN >=
 128) signals?
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From: Corinna Vinschen via Cygwin <cygwin@cygwin.com>
Reply-To: cygwin@cygwin.com
Cc: Corinna Vinschen <corinna-cygwin@cygwin.com>
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On Mar  3 23:07, Lionel Cons via Cygwin wrote:
> On Mon, 3 Mar 2025 at 12:43, Corinna Vinschen via Cygwin
> <cygwin@cygwin.com> wrote:
> >
> > On Feb 28 15:36, Lionel Cons via Cygwin wrote:
> > > We've hit a scalability issue in Cygwin today, the application in
> > > question ran out of POSIX realtime signals (i.e. SIGRTMIN-SIGRTMAX).
> > >
> > > Could Cygwin support 128 POSIX realtime signals?
> >
> > Not possible.  sigset_t is an unsigned long, thus we can only support
> > up to 64 signals.
> >
> > A change to a bigger sigset_t is an ABI breakage and requires two
> > different entry points for all functions touching the sigset_t type, one
> > for the new definition of sigset_t, one for backward compatibility with
> > existing applications.  This *could* be part of 3.7, but I don't make
> > any promises.
> 
> gcc has int128_t - would that help you?

Not at all.  It doesn't change the underlying problem of the ABI breakage.


Corinna

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