Re: Compiling in mingw-ucrt runtime

[Bruno Haible <bruno@clisp.org>]

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.

Bruno