Re: Compiling in mingw-ucrt runtime

[Eli Zaretskii <eliz@gnu.org>]

> 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.

> 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.