Re: Build error for wcwidth and gcvt

Corinna Vinschen <[email protected]> Tue, 23 Jul 2019 09:56:55 +0200
Newsgroups	gmane.comp.lib.newlib
Message-ID	<[email protected]>
On Jul 23 08:26, Kota Uchida wrote:
> I got understand about wchar_t data sizes.
> I fixed my patch and sent it:
> https://sourceware.org/ml/newlib/2019/msg00322.html
> 
> > The header should be kept untouched, of course.
> 
> The header file (wchar.h) must be fixed in order to
> match types between the header and .c file.

No, the header needs to stick to wchar_t since that's what the standard
says.  The wint_t for Cygwin is an internal implementation detail.


Corinna


> 
> On Mon, Jul 22, 2019 at 7:51 PM Corinna Vinschen <[email protected]> wrote:
> >
> > On Jul 22 11:46, Thomas Wolff wrote:
> > > On 22.07.2019 11:04, Corinna Vinschen wrote:
> > > > On Jul 20 17:50, Kota Uchida wrote:
> > > > > Hi All,
> > > > >
> > > > > This is my first mail to newlib community.
> > > > > I've send this mail because I found some build errors
> > > > > on newlib's master branch.
> > > > >
> > > > > Cygwin: unbreak the build with GCC 7
> > > > > 6b7723a83032bd355d3c529d957fe209cb35b4d9
> > > > >
> > > > > I encountered 2 errors about wcwidth and gcvt.
> > > > > I've pushed simple patches to forked repository:
> > > > > https://github.com/uchan-nos/newlib-cygwin/commits/fix-build
> > > The first patch is not correct:
> > > - wcwidth (const wint_t wc)
> > > + wcwidth (const wchar_t wc)
> > >
> > > Note the manual page.
> > > Even if you see the wchar_t definition for Linux/POSIX, note that wchar_t
> > > has 32 bits there.
> > > On cygwin, however, wchar_t was defined to have only 16 bits, corresponding
> > > to the Windows UTF-16 encoding.
> > > The wcwidth parameter type wint_t is needed to support width enquiries for
> > > non-BMP characters;
> > > changing it would seriously deprive the function of part of its
> > > capabilities.
> > > Thomas
> >
> > We might need a generic and a Cygwin-specific definition in the source, i.e.
> >
> >   #ifdef __CYGWIN__
> >   use wint_t
> >   #else
> >   use wchar_t
> >   #endif
> >
> > The header should be kept untouched, of course.
> >
> >
> > Corinna
> >
> > --
> > Corinna Vinschen
> > Cygwin Maintainer
> > Red Hat

-- 
Corinna Vinschen
Cygwin Maintainer
Red Hat
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