Hi, I am getting the following 7 link errors while making a release build of my application. (I had no problem making a debug build). //-------------------------------------------------------------------------------- RexEngine.obj : error LNK2001: unresolved external symbol "void __stdcall boost::re_detail::raise_regex_exception(class std::basic_string const &)" (?raise_regex_exception@re_detail@boost@@$$FYGXABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) RexEngine.obj : error LNK2001: unresolved external symbol "public: static class std::basic_string __stdcall boost::re_detail::w32_traits_base::error_string(unsigned int)" (?error_string@w32_traits_base@re_detail@boost@@$$FSG?AV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@I@Z) RexEngine.obj : error LNK2001: unresolved external symbol "protected: static bool __stdcall boost::reg_expression &,class std::basic_string const &)" (?transform_primary@?$w32_regex_traits@D@boost@@$$FSGXAAV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@ABV34@@Z) RexEngine.obj : error LNK2001: unresolved external symbol "public: static void __stdcall boost::w32_regex_traits<char>::transform(class std::basic_string &,class std::basic_string const &)" (?transform@?$w32_regex_traits@D@boost@@$$FSGXAAV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@ABV34@@Z) RexEngine.obj : error LNK2001: unresolved external symbol "void __stdcall boost::re_detail::verify_options(unsigned int,enum boost::regex_constants::_match_flags)" (?verify_options@re_detail@boost@@$$FYGXIW4_match_flags@regex_constants@2@@Z) //-------------------------------------------------------------------------------- Any idea why these function calls failed to be linked. (does it has to do with the calling convention __fastcall being changed to __stdcall?) I have tried making BOOST_REGEX_CALL __cdecl to no avail. Help please ! Thanks in advance, Steve