On Thu, Mar 3, 2011 at 12:02 PM, Matthias Schabel <boost@schabel-family.org> wrote:
I don't really understand what you're trying to accomplish.

I'm trying to add two quantities together. One quantity was created using the si system and the other was created directly.

Maybe http://www.boost.org/doc/libs/1_46_0/doc/html/boost_units/Quantities.html#boost_units.Quantities.Quantity_Construction_and_Conversion?

I thought what this meant was a quantity value was being creating with the si::length dimension. The unit of measurement for si::length is the meter and therefore the value 2.0 is being stored as 2.0 meters. I thought this was confirmed when the display of the quantity value showed "2 m". If this isn't what is occurring could you shed some light on this?

quantity<si::length> is shorthand for quantity<si::length,double>. si::length is type representing a length in the SI system, so it encapsulates both the dimensionality of length and the specific measure of length.