id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
12308	Quantities cannot be sent to std::ostream	gunnar.arndt@…	Matthias Schabel	"Compiling the following program 
{{{
#include <iostream>

#include ""boost/units/systems/si.hpp""
#include ""boost/units/quantity.hpp""

int main() {
    boost::units::quantity<boost::units::si::electric_potential> quantity = 1 * boost::units::si::volt;
    std::cout << quantity;
	return 0;
}

}}}
that sends a quantity to a std::ostream with operator<< result in the following error message:

{{{
13:51:55 **** Incremental Build of configuration Debug for project Test ****
Info: Internal Builder is used for build
g++ -std=c++0x ""-IC:\\firedect\\git\\boost"" -O0 -g3 -Wall -c -fmessage-length=0 -o ""src\\Test.o"" ""..\\src\\Test.cpp"" 
..\src\Test.cpp: In function 'int main()':
..\src\Test.cpp:8:18: error: cannot bind 'std::ostream {aka std::basic_ostream<char>}' lvalue to 'std::basic_ostream<char>&&'
     std::cout << quantity;
                  ^
In file included from c:\mingw\lib\gcc\mingw32\4.9.3\include\c++\iostream:39:0,
                 from ..\src\Test.cpp:1:
c:\mingw\lib\gcc\mingw32\4.9.3\include\c++\ostream:602:5: note: initializing argument 1 of 'std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&&, const _Tp&) [with _CharT = char; _Traits = std::char_traits<char>; _Tp = boost::units::quantity<boost::units::unit<boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-3l> >, boost::units::list<boost::units::dim<boost::units::current_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> > > > > > > > > > > >]'
     operator<<(basic_ostream<_CharT, _Traits>&& __os, const _Tp& __x)
     ^

13:51:56 Build Finished (took 1s.190ms)
}}}
I got a little nervous when I noticed that old #6119 seems to describe the same problem, although I don't get what it has to do with Intel and Leopard?
I hope I've just made a stupid mistake in my code."	Bugs	closed	To Be Determined	units	Boost 1.61.0	Showstopper	invalid	quantity ostream operator<< g++