In my project (using asio) I have something like this: void Foo::myCallback(const boost::system::error_code &e) { if(e == boost::asio::error::operation_aborted) { // bla bla... } } This call is made across a shared dll and I notice that for a "strange" reason e == boost::asio::error::operation_aborted was always false. I discover that when the temporary object boost::system::error_code is constructed from the constants boost::asio::error::operation_aborted the error_code's costructor take a pointer to a "error_category" and the comparison operator is (m_cat is an error_category pointer): inline friend bool operator==( const error_code & lhs, const error_code & rhs ) { return lhs.m_cat == rhs.m_cat && lhs.m_val == rhs.m_val; } In my situation (using shared modules) lhs.m_cat == rhs.m_cat points to differents memory regions (even if are of the same type "system_category") because of the static initialization in the function "get_system_category". The problem exist in the comparison operator of error_category too: bool operator==(const error_category & rhs) const { return this == &rhs; } I suggest to change the comparison criteria (for example using an enumerated value) _________________________________________________________________ Sai che con Messenger guardi la TV con i tuoi amici? http://www.messenger.it/messengertv.html