[Boost-users] boost/units - converting forces (lbf->N)

Thanks for response....Yes, yes, yes.  I get that.  I am having trouble understanding the library; not force.  (Same as last time) I guess I thought the library was magically accounting for gravity which is an error. Updated:https://coliru.stacked-crooked.com/a/d256de6c16bdb08f Thank you, On Saturday, December 1, 2018, 9:10:38 AM CST, degski wrote: On Sat, 1 Dec 2018 at 15:26, Matt Vinson via Boost-users wrote: To see if I understand the library, I want to create metric and imperial systems without using Boost Units predefined systems*.  Conversions between lengths are going well.  Conversion between forces are going well until pounds-force to newtons; line 182 in the link.  What am I doing wrong when lbf will not convert to newtons? Gravity is not your friend [and gets in the way of what you want to do], you're not doing anything wrong [C++-wise], but you're converting hamburgers to cheeseburgers [for free], they don't convert.

From Wikipedia (https://en.wikipedia.org/wiki/Pound_(force)): The pound-force is equal to the gravitational force exerted on a mass of one avoirdupois pound on the surface of Earth. Since the 18th century, the unit has been used in low-precision measurements, for which small changes in Earth's gravity (which varies from place to place by up to half a percent) can safely be neglected.[4]

The 20th century, however, brought the need for a more precise definition. A standardized value for acceleration due to gravity was therefore needed. degski -- “If something cannot go on forever, it will stop" - Herbert Stein