int GetUsers(GET_USERS::CALLBACK f, void * data);
int GetUser(const std::string & login, GET_USER::CALLBACK f, void * data);
int ChgUser(const std::string & request, CHG_USER::CALLBACK f, void * data);
int AuthBy(const std::string & login, AUTH_BY::CALLBACK f, void * data);
int SendMessage(const std::string & request, SEND_MESSAGE::CALLBACK f, void * data);
int GetUsers(GET_USERS::CALLBACK f, void * data);
int GetUser(const std::string & login, GET_USER::CALLBACK f, void * data);
int ChgUser(const std::string & request, CHG_USER::CALLBACK f, void * data);
int AuthBy(const std::string & login, AUTH_BY::CALLBACK f, void * data);
int SendMessage(const std::string & request, SEND_MESSAGE::CALLBACK f, void * data);