[Boost-bugs] [Boost C++ Libraries] #12708: Cannot use Boost Units cmath.hpp with custom systems

Subject: [Boost-bugs] [Boost C++ Libraries] #12708: Cannot use Boost Units cmath.hpp with custom systems
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2016-12-22 08:11:53

#12708: Cannot use Boost Units cmath.hpp with custom systems
-----------------------------------------------+---------------------------
 Reporter:  Kamil Rojewski <kamil.rojewski@…>  |      Owner:
     Type:  Bugs                               |  matthiasschabel
Milestone:  To Be Determined                   |     Status:  new
  Version:  Boost 1.62.0                       |  Component:  units
 Keywords:                                     |   Severity:  Problem
-----------------------------------------------+---------------------------
 When creating a new, custom unit sustem in Boost Units using
 boost::units::make_system, there's an issue when including cmath.hpp:


 {{{
 In file included from boost/boost/units/cmath.hpp:29:
 In file included from boost/boost/units/systems/si/plane_angle.hpp:14:
 In file included from boost/boost/units/systems/si/base.hpp:20:
 In file included from boost/boost/units/base_units/si/meter.hpp:17:
 /boost/boost/units/base_unit.hpp:108:9: error: functions that differ only
 in their return type cannot be overloaded
         check_double_register(const units::base_unit_ordinal<N>&)
         ^
 Common/Units.h:26:15: note: in instantiation of template class
 'boost::units::base_unit<VA::Units::SquareBaseUnit,
 boost::units::list<boost::units::dim<boost::units::length_base_dimension,
       boost::units::static_rational<1, 1> >,
 boost::units::dimensionless_type>, -9, void>' requested here
             : boost::units::base_unit<SquareBaseUnit,
 boost::units::length_dimension, -9>
               ^
 boost/boost/units/base_unit.hpp:108:9: note: previous declaration is here
         check_double_register(const units::base_unit_ordinal<N>&)
         ^
 boost/boost/units/base_unit.hpp:114:9: error: redefinition of
 'boost_units_unit_is_registered'
 }}}


 As you can see, cmath includes the full si system and you cannot make your
 own after that.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/12708>
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