Hi Vicente, Thank you for the reply. When I took a look at codes under "thread', I found there are some places where BOOST_NO_ANSI_APIS is related ( for example in once.hpp ) #ifdef BOOST_NO_ANSI_APIS     typedef wchar_t once_char_type #else     typedef char once_char_type #endif There is no relation between both librairies that I'm aware of. If you are more explicit with the  problem you have, maybe we can help you better. Best, Vicente BTW, don't top post and please send message in text only mode.