Re: Compiling in mingw-ucrt runtime

[Arthur Miller <arthur.miller@live.com>]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Bruno Haible <bruno@clisp.org>
>> Cc: arthur.miller@live.com, emacs-devel@gnu.org
>> Date: Sun, 25 Feb 2024 16:32:59 +0100
>> 
>> On Sonntag, 25. Februar 2024 16:14:51 CET Eli Zaretskii wrote:
>> > > From: Bruno Haible <bruno@clisp.org>
>> > > Cc: arthur.miller@live.com, emacs-devel@gnu.org
>> > > Date: Sun, 25 Feb 2024 16:05:54 +0100
>> > > 
>> > > > Strange that they claim that, because their sources tell a different
>> > > > story, both for MSVCRT and for UCRT.  Or maybe your interpretation of
>> > > > what they say there is inaccurate?
>> > > 
>> > > Re MSVCRT: My reading of Vc7/crt/src/fclose.c is that it never sets errno.
>> > 
>> > fclose.c doesn't, indeed, but it calls _close (in close.c), which
>> > does.
>> 
>> OK, so when it calls _close() and that fails, errno gets set. Good.
>> Still, fclose() can also fail due to !inuse(stream), in which case errno does
>> not get set.
>> 
>> > > Re UCRT: My reading of ucrt-10.0.10240.0/stdio/fclose.cpp
>> > > and 10.0.14393.0/ucrt/stdio/fclose.cpp
>> > > is that errno gets set to EINVAL if the stream argument is invalid,
>> > > and remains unchanged otherwise.
>> > 
>> > I do see errno being set in close.cpp, which fclose.cpp calls to do
>> > the actual job.
>> 
>> Likewise here: Still, fclose() can also fail due to !stream.is_in_use(), in
>> which case errno does not get set.
>
> Yes, I agree that it doesn't set errno in all the cases where it
> fails.  But that's a far cry from saying that errno is always
> undefined after it fails.
>
> And the question still stands why does it fail in Emacs in such a way.

Just a short question: did you got anywhere further with this?

Where did you look at the source? Are they installed with their (MS) command
line tools or do I have to install the entire VS/Windows devkti for the sources?