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Date: Fri, 21 Nov 2025 17:46:42 +0100
To: cygwin AT cygwin DOT com
Subject: Re: dynamic conpty loading
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From: Corinna Vinschen via Cygwin <cygwin AT cygwin DOT com>
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Hi Thomas,

On Nov 21 16:46, Thomas Wolff via Cygwin wrote:
> Am 21.11.2025 um 11:04 schrieb Takashi Yano via Cygwin:
> > On Sun, 5 Oct 2025 10:15:55 +0200
> > Thomas Wolff wrote:
> > > > > The procedure seems to be:
> > > > > try LoadLibrary("conpty.dll"), (if not successful, fallback to
> > > > > GetModuleHandle("kernel32") instead) to retrieve GetProcAddress for
> > > > > CreatePseudoConsole, ResizePseudoConsole, ClosePseudoConsole, and
> > > > > then somehow (?) use those while calling CreateProcess.
> > > > > The latter is woven into the cygwin library and I don't think it's a
> > > > > good idea to clone that out of cygwin for a patched process creation
> > > > > in mintty.
> > > > > 
> > > > > My question/suggestion:
> > > > > Can a cygwin mode switch to a selected conpty library instead of the
> > > > > default one please?

Where do you expect this conpty.dll to reside?  

If we do something like that, I would suggest to make sure that this
conpty.dll is in a well-defined place. /bin or /lib might be a good
idea. And if it exists in this defined place, it will be used by Cygwin.

We can tweak the autoload mechanism to allow a primary DLL and a fallback
DLL, that drops the need to set the CYWIN env var.

The mintty package could contain a post-install script, or some other
script in /bin to allow a user with admin rights downloading the latest
(or the most sensible) conpty.dll from MSFT.

Would that make sense?


Corinna

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