Re: [Boost-users] boost serialization compilation and WCHAR

From: Brian Budge (brian.budge_at_[hidden])
Date: 2006-05-09 23:59:15

Oops, looks like I spoke too soon.  I just tried solution (1) below,
and although now boost compiles the serialization library, when I
compile something using boost, I can't link against several symbols
utilizing wide characters.

The real problem, it looks like, is that libstdc++ STILL REFERS to
USE_WCHAR_T even though it forgets to define it.  Hence, when
libstdc++ is building, it doesn't build wchar support into the
libraries.

So apparently, solution (1) IS the solution, and the libstdc++ guys
(or something else in the system that helps libstdc++ detirmine wchar
support) will have to fix this.

Thanks, and sorry for the noise.

  Brian

On 5/9/06, Brian Budge <brian.budge_at_[hidden]> wrote:
> Hi all -
>
> I'm running into problems building the serialization library with gcc
> 4.1.  I tracked it down to a change in libstdc++ for gcc 4.1 from the
> gcc 3.x libstdc++.
>
> I'm sure there's a bug, but I'm not sure if it is a boost bug, a
> libstdc++ bug, or a gcc 4.1 bug.
>
> boost_1_33_1/boost/config/stdlib/libstdcpp3.hpp says:
>
> #if !defined(_GLIBCPP_USE_WCHAR_T) && !defined(_GLIBCXX_USE_WCHAR_T)
> #  define BOOST_NO_CWCHAR
> #  define BOOST_NO_CWCTYPE
> #  define BOOST_NO_STD_WSTRING
> #  define BOOST_NO_STD_WSTREAMBUF
> #endif
>
> and indeed, with the 4.1 compiler, neither define is defined.  For 4.1 in file
>
> /usr/lib/gcc/i686-pc-linux-gnu/4.1.0/include/g++-v4/i686-pc-linux-gnu/c++config.h
>
> I have
> /* Defined if vfwscanf exists. */
> #define _GLIBCXX_HAVE_VFWSCANF 1
>
> /* Defined if vswscanf exists. */
> #define _GLIBCXX_HAVE_VSWSCANF 1
>
> /* Defined if vwscanf exists. */
> #define _GLIBCXX_HAVE_VWSCANF 1
>
> /* Define to 1 if you have the <wchar.h> header file. */
> #define _GLIBCXX_HAVE_WCHAR_H 1
>
> /* Defined if wcstof exists. */
> #define _GLIBCXX_HAVE_WCSTOF 1
>
> /* Define to 1 if you have the <wctype.h> header file. */
> #define _GLIBCXX_HAVE_WCTYPE_H 1
>
> (no reference to USE_WCHAR_T)
>
> and in
>
> /usr/lib/gcc/i686-pc-linux-gnu/3.4.5/include/g++-v3/i686-pc-linux-gnu/bits/c++config.h
>
> I have
> // Define if code specialized for wchar_t should be used.
> #define _GLIBCXX_USE_WCHAR_T 1
>
> my fix would be one of three things:
>
> 1) in c++config.h
> #define _GLIBCXX_USE_WCHAR_T
>
> 2) in libstdcpp3.hpp add a test for _GLIBCXX_HAVE_WCHAR_H:
> #if !defined(_GLIBCPP_USE_WCHAR_T) && !defined(_GLIBCXX_USE_WCHAR_T)
> && !defined(_GLIBCXX_HAVE_WCHAR_H)
> #  define BOOST_NO_CWCHAR
> #  define BOOST_NO_CWCTYPE
> #  define BOOST_NO_STD_WSTRING
> #  define BOOST_NO_STD_WSTREAMBUF
> #endif
>
> 3) somewhere else
> #ifdef _GLIBCXX_HAVE_WCHAR_H
> #define _GLIBCXX_USE_WCHAR_T
> #endif
>
> What do you guys think?
>
>   Brian
>