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.

That explains why "si::length" and "meters" are different things...basically, "meters" is an instance of si::length.

quantity<si::length> L = 2.0 * meters;

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?

Ryan