Re: [PATCH] Fix libstdc++ usage of __ctype_b/__ctype_to*

[Jakub Jelinek <jakub at redhat dot com>]

On Wed, Sep 04, 2002 at 04:05:57PM -0500, Benjamin Kosnik wrote:
> > -#if _GLIBCPP_USE_SHADOW_HEADERS
> > +#if _GLIBCPP_C_LOCALE_GNU
> > +  const ctype_base::mask*
> > +  ctype<char>::classic_table() throw()
> > +  {
> > +    if (!_S_c_locale)
> > +      _S_create_c_locale(_S_c_locale, "C");
> > +    return _S_c_locale->__ctype_b;
> > +  }
> > +#else
> 
> _S_c_locale should be created before this. I suppose this is safer.

Most probably yes, but as it is a static method I wanted to be sure.
Should I leave it in?

> > +# if _GLIBCPP_USE_SHADOW_HEADERS
> >    using _C_legacy::__ctype_toupper;
> >    using _C_legacy::__ctype_tolower;
> >    using _C_legacy::__ctype_b;
> > -#endif
> 
> Just remove all this _GLIBCPP_USE_SHADOW_HEADERS cruft.

You mean the using lines too?

> > +# endif
> >  
> >    const ctype_base::mask*
> >    ctype<char>::classic_table() throw()
> > -  { return __ctype_b; }  
> 
> Why not just _S_c_locale->__ctype_b?

Well, I use _S_c_locale->__ctype_b #ifdef _GLIBCPP_C_LOCALE_GNU,
otherwise _S_c_locale is NULL (config/locale/generic/c_locale.cc has:
  void
  locale::facet::_S_create_c_locale(__c_locale& __cloc, const char*,
                                    __c_locale)
  { __cloc = NULL; }
) and it is a bad idea to dereference it...

> 
> > -  
> > +  {
> > +    const ctype_base::mask* __ret;
> > +    char* __old = strdup(setlocale(LC_CTYPE, NULL));
> > +    setlocale(LC_CTYPE, "C");
> > +    __ret = __ctype_b;

BTW: This will have the effect that --enable-clocale=generic will no longer
work with glibc 2.3+. Although for everything but checking the generic
clocale gnu it makes no sense to use anything but --enable-clocale=gnu
with glibc 2.3+, we might as well consider using:

#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
	__ret = *__ctype_b_loc();
#else
	__ret = __ctype_b;
#endif
here (and similarly with __ctype_tolower and __ctype_toupper).

> > +    setlocale(__old);
> > +    free(__old);
> > +    return __ret;
> > +  }
> > +#endif
> 
> Ok. Make sure the generic/ctype_noninline.h also does this though.

generic/ctype_noninline.h doesn't use __ctype_b and it cannot anyway,
since __ctype_b is (well, was) a glibc thing, so it has nothing to do
in generic header.
> 
> > +
> >  #if _GLIBCPP_C_LOCALE_GNU
> 
> all these hooks are in the gnu-linux file so that --enable-clocale=generic
> will work on linux, so that I can test the generic codepath on checkins.

	Jakub