I've notices something right now:
__PURE_APPDOMAIN_GLOBAL static std::locale::_Locimp *global_locale = 0; // pointer to current locale
Ok, this is interesting point... Make sure that all DLLs you are using are compiled correctly with Same MSVC runtime **DLL** (with correct import flags) and not mixed DLL/static library/ Because if they are not, there may be more then one instance of std::locale::_Locimp *global_locale = 0; If it was not exported! foo.dll -> uses dllexported std::locale::_Locimp *global_locale bar.dll -> uses dllexported std::locale::_Locimp *global_locale baz.dll -> do not import symbol of std::locale::_Locimp *global_locale and uses its own version. And you end with two static variables that are not merged... It is very unplesant issue (which makes me love ELF and shared objects ;-) ). When using Boost.Locale or any std::locale faces on your own you must make sure that all DLLs and libraries same MSVC DLL. Otherwise... wellcome to hell. Artyom