Boost QVM

col

#include <boost/qvm/map_mv.hpp>

namespace boost
{
    namespace qvm
    {
        //Only enabled if: is_m<A>::value
        template <int C,class A>
        -unspecified-return-type- col( A & a );
    }
}

The expression col<C>(m) returns a view proxy that accesses column C of the matrix m as a vector.

See also: boost/qvm/map_mv.hpp