Re: [Boost-users] [units] Unable to print temperature quantity

Subject: Re: [Boost-users] [units] Unable to print temperature quantity
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 2011-11-12 09:04:31

Le 12/11/11 06:55, Belcourt, K. Noel a écrit :
> Hi,
>
> I'm a complete neophyte with the units library.  I have cause to use 
> it so I'm trying to do something simple and am getting compile 
> problems.  This code:
>
> #include <iostream>
> #include <boost/units/io.hpp>
> #include <boost/units/quantity.hpp>
> #include <boost/units/systems/temperature/fahrenheit.hpp>
>
> int main(int, char **) {
>  using namespace boost::units;
>  quantity<fahrenheit::temperature> t;
>  std::cout << t << std::endl;
>  return 0;
> }
>
> Generates this error with Intel 11.1 on Darwin using trunk.
>
> /Users/kbelco/boost/boost/units/io.hpp(967): error: more than one 
> instance of overloaded function 
> "boost::units::detail::do_print_prefixed" matches the argument list:
>            function template "void 
> boost::units::detail::do_print_prefixed<Prefixes,CharT,Traits,Dimension,System,T>(std::basic_ostream<_CharT, 
> _Traits> &, const boost::units::quantity<boost::units::unit<Dimension, 
> System, void>, T> &)"
>            function template "void 
> boost::units::detail::do_print_prefixed<Prefixes,CharT,Traits,Unit,T>(std::basic_ostream<_CharT, 
> _Traits> &, const boost::units::quantity<Unit, T> &)"
>            argument types are: (std::basic_ostream<char, 
> std::char_traits<char>>, const 
> boost::units::quantity<boost::units::fahrenheit::temperature, double>)
>      detail::do_print_prefixed<Prefixes>(os, q);
>      ^
>          detected during:
>            instantiation of "void 
> boost::units::detail::maybe_print_prefixed<Prefixes,CharT,Traits,Unit,T>(std::basic_ostream<_CharT, 
> _Traits> &, const boost::units::quantity<Unit, T> &, 
> boost::mpl::true_) [with 
> Prefixes=boost::units::detail::engineering_prefixes, CharT=char, 
> Traits=std::char_traits<char>, 
> Unit=boost::units::fahrenheit::temperature, T=double]" at line 1050
>            instantiation of "std::basic_ostream<_CharT, _Traits> 
> &boost::units::operator<<(std::basic_ostream<_CharT, _Traits> &, const 
> boost::units::quantity<Unit2, T2> &) [with Char=char, 
> Traits=std::char_traits<char>, 
> Unit=boost::units::fahrenheit::temperature, T=double]" at line 14 of 
> "/Users/kbelco/core_simulator/test/integration/main_test_5.cpp"
>
> Any ideas what I'm doing wrong?
>
>
Hi,

I think this is a bug in Boost.Units. I suspect that the call to 
detail::do_print_prefixed<Prefixes>(os, q) will not use overload 
resolution as it is used with <Prefixes>.

HTH,
Vicente