Ovanes, sorry, I made an error when writing the sample. It should have been: template <typename T> struct point : boost::additive { T x_; T y_; explicit point(T x=0, T y=0) : x_(x), y_(y) { } point & operator += (T offset) { x_ += offset; y_ += offset; return *this; } point & operator -= (T offset) { x_ -= offset; y_ -= offset; return *this; } } This part is working as it should. My problem comes as soon as I make member templates out of the operators, for example like so ... template <typename U> point & operator += (U offset) { x_ += offset; y_ += offset; return *this; } ... How do I write the boost::additive stuff so that it works with the operator template with all the types U that are instantiated? Is that at all possible? Peter "Ovanes Markarian" schrieb im Newsbeitrag news:a83c1a380804250223i4e3cbcdfu17871dfb0a585600@mail.gmail.com... Peter, AFAIK operator += or operator -= signature must contain a return value. In your case it can probably be void. template<class U> void operator+=(U offset) { ... } ... Best Regards, Ovanes On Fri, Apr 25, 2008 at 10:41 AM, Peter wrote: Assuming I have a class like the following: template <typename T> struct point : boost::additive { T x_; T y_; explicit point(T x=0, T y=0) : x_(x), y_(y) { } operator += (T offset) { x_ += offset; y_ += offset; } operator -= (T offset) { x_ -= offset; y_ -= offset; } } Now I want to change the addition and subtraction operators to allow for different types using the following template class point ... template <typename U> operator += (U offset) { x_ += offset; y_ += offset; } template <typename U> operator -= (T offset) { x_ -= offset; y_ -= offset; } ... I cannot figure out how to write the proper syntax for the boost::additive class, so that it generates the proper additional operators for all type combinations. Is that possible, at all? Thanks, Peter _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users ------------------------------------------------------------------------------ _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users