# QVM: Quaternions, Vectors, Matrices

### Indexing Vector Elements

#include <boost/qvm/mat_access.hpp>

    namespace boost
    {
        namespace qvm
        {
            //*** Indexing vector elements ***

            //Only enabled if:
            //  is_vec<A>::value
            template <class A>
            typename vec_traits<A>::scalar_type
            vec_index_read( A const & a, int i );

            //Only enabled if:
            //  is_vec<A>::value
            template <class A>
            typename vec_traits<A>::scalar_type &
            vec_index_write( A & a, int i );
        }
    }

See also: Synopsis