const boost::array<T,N> or boost::array<const T,N>?

Question

What is difference between these two? Which one you would prefer when you need a fixed size array of constant values?

const boost::array<int, 2> x = {0, 1};
boost::array<const int, 2> y = {0, 1};

Thanks.

Answer 1

The second one will prevent that you copy it to a new non-const array

boost::array<const int, 2> y = {0, 1};
boost::array<int, 2> y1 = y; // error!

Since I would expect that to work, I would probably go with the first option. Passing the second one to templates that expect a boost::array<T, N> will prevent those templates from modifying their parameter (even if it's a copy). The first one would "just work", since the parameter would have the type boost::array<int, 2>.