$ g++ transc.cpp
In file included from /usr/include/boost/numeric/interval/hw_rounding.hpp:15:0,
                 from /usr/include/boost/numeric/interval.hpp:18,
                 from transc.cpp:12:
/usr/include/boost/numeric/interval/rounded_arith.hpp: In instantiation of ‘T boost::numeric::interval_lib::rounded_arith_opp<T, Rounding>::int_down(const T&) [with T = double; Rounding = boost::numeric::interval_lib::rounding_control<double>]’:
/usr/include/boost/numeric/interval/arith2.hpp:40:49:   required from ‘boost::numeric::interval<T, Policies> boost::numeric::fmod(const boost::numeric::interval<T, Policies>&, const boost::numeric::interval<T, Policies>&) [with T = double; Policies = boost::numeric::interval_lib::policies<boost::numeric::interval_lib::detail::save_state_unprotected<full_rounding>, boost::numeric::interval_lib::checking_strict<double> >]’
/usr/include/boost/numeric/interval/transc.hpp:62:32:   required from ‘boost::numeric::interval<T, Policies> boost::numeric::cos(const boost::numeric::interval<T, Policies>&) [with T = double; Policies = boost::numeric::interval_lib::policies<boost::numeric::interval_lib::save_state<full_rounding>, boost::numeric::interval_lib::checking_strict<double> >]’
transc.cpp:78:3:   required from here
/usr/include/boost/numeric/interval/rounded_arith.hpp:108:45: error: ‘to_int’ was not declared in this scope, and no declarations were found by argument-dependent lookup at the point of instantiation [-fpermissive]
/usr/include/boost/numeric/interval/rounded_arith.hpp:108:45: note: declarations in dependent base ‘boost::numeric::interval_lib::detail::c99_rounding_control’ are not found by unqualified lookup
/usr/include/boost/numeric/interval/rounded_arith.hpp:108:45: note: use ‘this->to_int’ instead
$