AMDG On 09/27/2011 11:06 PM, Ben Robinson wrote:
The required modification to Boost Unit, was to add the following templated constructor to boost::units::quantity:
template <class rhs_type> quantity(const rhs_type& source) : val_() { BOOST_METATEST_MSG(false, INVALID_CONVERSION_BETWEEN_INCOMPATIBLE_UNITS, (this_type, rhs_type)); }
In the unmodified library, the lack of this constructor would produce the compiler error, when an incorrect assignment requiring this constructor was made. This makes an interesting point, that I have written additional code to *explicitly* express the intended failure consequence of invoking this constructor, instead of relying *implicitly *on the lack of such a definition.
Unfortunately, this changes the behavior of the library. is_convertible<Q1, Q2> will return true if the units are unrelated. It can also change the result of overload resolution. In Christ, Steven Watanabe