Re: [boost] Visual Studio 2015 Update 3 has removed std::unary_function and std::binary_function

I seem to recall when I used boost::iterator::transform_iterator (which requires a UnaryFunction in its template argument), if I did not derive from std::unary_function I got a bunch of compile errors. This is because some part of the iterator implementation is looking for those nested types. So while the transform_iterator implementation itself does not depend on std::unary_function, it does depend on some or all of those types being present. I'm not sure if this affects the discussion taking place here or not, or what changes are needed if any - apologies if it is noise.