Re: [Boost-users] [units] Creating a velocity unit

Subject: Re: [Boost-users] [units] Creating a velocity unit
From: Ryan (boost_at_[hidden])
Date: 2013-02-21 13:25:48

Thanks for the link it was helpful.  I tried both methods and they both
compiled.  It seems we can use the simpler form of decltype because it
provides perfect forwarding.  Is this a correct interpretation?

Neither of these two typedef seems to behave as I expected.  When creating
a quantity with these typedefs I had to call them as a method to get the
code to compile.

quantity<si::velocity> a(2.3 * nautical_miles_per_hour1());
quantity<si::velocity> b(2.4 * nautical_miles_per_hour2());
quantity<si::velocity> c(2.5 * si::meters_per_second);

Is there a way to get my type of nautical_miles_per_hour to behave like
meters_per_second?

Ryan

//Provided for the Discussion
using namespace boost::units;
typedef metric::nautical_mile_base_unit::unit_type  nautical_mile_unit;
typedef metric::hour_base_unit::unit_type  hour_unit;

typedef decltype(nautical_mile_unit() / hour_unit())
 nautical_miles_per_hour1;
typedef divide_typeof_helper<nautical_mile_unit, hour_unit>::type
 nautical_miles_per_hour2;