Re: [Boost-users] msvc fail to link with dynamic boost_program_options library

Hi all, In case anyone is still interested... With the release of Boost 1.41 I looked into this problem again and found out it was my own mistake. When linking to a DLL of boost_program_options (in my case without autolinking), I got two unresolved symbols to the following "global" variables: boost::options_description::m_default_line_length and boost::program_options::arg The problem was in my CMakeLists.txt file, where I assumed that setting Boost_USE_STATIC_LIBS to Off would be sufficient. In that case BOOST_ALL_DYN_LINK is not defined. As a consequence the definition of BOOST_PROGRAM_OPTIONS_DECL was empty when importing the library, hence no __declspec( dllimport ) and correspondingly a linker-error. I don't know if this is the solution for the others, but by explicitly defining BOOST_ALL_DYN_LINK (or BOOST_PROGRAM_OPTIONS_DYN_LINK) I can now link my apps to a boost_program_options dll. Regards, André On Wed, Oct 14, 2009 at 2:44 PM, Vladimir Prus wrote:

André Prins wrote:

...

Hi all,

I am having exactly the same problems when trying to link my main-app to a DLL-version of Boost::program_options. (using MSVC 9 and Boost 1.40).

...

main.obj : error LNK2001: unresolved external symbol "public: static unsigned int const boost::program_options::options_description::m_default_line_length" (?m_default_line_length@options_description@program_options@boost@@2IB)

For the first unresolved external, to the options_description::m_default_line_length, there is a workaround, by explicitly specifying a line-length as the second argument when constructing your descriptions. E.g.

    po::options_description descriptions( "All options", 80 ); // Note the extra argument 80

...

main.obj : error LNK2001: unresolved external symbol "class std::basic_string boost::program_options::arg" (?arg@program_options@boost@@3V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@A)

For the second unresolved external, I could not find a solution and I decided to build a static version of Boost::program_options. This solved both of these two problems.

It would be nice if somebody figure what this problem is and explain this to me. Or provide a patch ;-)

- Volodya

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