[boost] Compiling program_options v1.35 on msvc9.0 fix

From: evert.vandewaal_at_[hidden]
Date: 2008-08-15 04:53:44

Hi All,

I have had some problems compiling program_options v1.35 on visual C++ 9.0
(2008) Express. It seems that this compiler does not correctly export some
global variables when compiling to DLL, leading to unresolved dependencies.
I have had to make a few changes:

In file options_description.hpp, line 158:

Replaced

        static const unsigned m_default_line_length;

with

        BOOST_STATIC_CONSTANT (unsigned, m_default_line_length = 80);

This is an old fix that I found in the mail archives (2005), seems to have
been erroneously dropped from the base-line.

In file options_description.cpp: removed the declaration of
m_default_line_length.

In file value_semantic.cpp: a singleton variable was defined but not
properly linked by vc9.0. I changed the implementation to (line 17)

          BOOST_PROGRAM_OPTIONS_DECL string&

          arg()

          {

            static string* str=0;

            if (!str)

            {

              str = new string;

              *str = "arg";

            }

            return *str;

          }

At line 79 (after making the change above), I changed the only use of arg
to:

          std::string

          untyped_value::name() const

          {

              return arg();

          }

In file details/value_semantic.hpp: I changed the declaration of the
variable arg to (line 13):

      BOOST_PROGRAM_OPTIONS_DECL std::string& arg();

After these changes, program_options links properly, and I was able to run
the demo code.

Please note that also the pre-compiled version of boost 1.35 for the vc9.0
compiler from http://www.boost-consulting.com/download/windows suffers from
these problems: the program_options DLL is unlinkable due to unresolved
references to m_default_line_length  and arg.

Cheerio,

Evert van de Waal