[Boost-bugs] [Boost C++ Libraries] #12766: Boost Units: Quantities in Constexpr Functions

Subject: [Boost-bugs] [Boost C++ Libraries] #12766: Boost Units: Quantities in Constexpr Functions
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2017-01-17 10:37:44

#12766: Boost Units: Quantities in Constexpr Functions
-------------------------------------+-----------------------------
 Reporter:  a.huebl@…                |      Owner:  matthiasschabel
     Type:  Feature Requests         |     Status:  new
Milestone:  To Be Determined         |  Component:  units
  Version:  Boost 1.62.0             |   Severity:  Problem
 Keywords:  units literal constexpr  |
-------------------------------------+-----------------------------
 I would like to use boost quantities in C++11 constexpr functions (and
 later C++14 constexpr functions). Unfurtunately, I can not define a simple
 quantity as constexpr:



 {{{
 #include <boost/units/systems/si.hpp>
 #include <boost/units/quantity.hpp>

 using namespace boost::units;

 constexpr quantity< si::length, double >  dtestExt{ 0.2e-6 };
 // or
 constexpr quantity< si::length, double >  dtestExt = 0.2e-6;
 }}}


 g++ -std=c++11 (4.9.4):

 {{{
 error: the type ‘
 const boost::units::quantity<
   boost::units::unit<
     boost::units::list<
       boost::units::dim<
         boost::units::length_base_dimension,
         boost::units::static_rational<1l>
       >,
       boost::units::dimensionless_type
     >,
     boost::units::homogeneous_system<
       boost::units::list<
         boost::units::si::meter_base_unit,
 boost::units::list<boost::units::scaled_base_unit<boost::units::cgs::gram_base_unit,
 boost::units::scale<10l, boost::units::static_rational<3l> > >,
         boost::units::list<boost::units::si::second_base_unit,
 boost::units::list<boost::units::si::ampere_base_unit,
 boost::units::list<boost::units::si::kelvin_base_unit,
 boost::units::list<boost::units::si::mole_base_unit,
 boost::units::list<boost::units::si::candela_base_unit,
 boost::units::list<boost::units::angle::radian_base_unit,
 boost::units::list<boost::units::angle::steradian_base_unit,
 boost::units::dimensionless_type> > > > > >
           >
         >
       >
     >
   >
 >’
 of constexpr variable ‘dtestExt’ is not literal

 }}}

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/12766>
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