If Cygwin is installed, open-tls-stream works, because gnutls-cli and
openssl are available. It has worked for some time. I routinely use this
feature to enable ERC to connect to servers using TLS using function
erc-tls.

This bug report is about an Elisp logic error that can happen on any
platform if the certificate trust files do not exist, leading to a
malformed gnutls-cli command line. Those files are outside the control of
Emacs. They may not exist.

Please don't disable functionality that some of us have used for years.

Thanks.
--
Fran Litterio
On Jun 13, 2016 6:18 AM, "Lars Ingebrigtsen" <larsi@gnus.org> wrote:

Eli Zaretskii <eliz@gnu.org> writes:

> TLS connections on MS-Windows are supported via the GnuTLS library.
> External TLS programs will never work correctly on Windows, since they
> use signals to communicate with Emacs.  So there's little sense in
> fixing this issue, because the result will not work anyway.

Perhaps it would make sense to just have `open-tls-stream' signal an
error on Windows to avoid confusing people?  I think this is at least
the fourth bug report where people have spent significant time trying to
debug something that will never work.

It could just say (error "Use an Emacs built with TLS support (and with
installed gnutls libraries)").

--
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no