Using std::extent on std::array

Question

I have a templatized function and I want to static_assert that it\'s type has a size of three. This code illustrates what I\'m trying to do, but doesn\'t work:<

Answer 1

I can't think of a way to write a single function that handles both, but this is what overloading is for.

template 
void check_array_size( T (&)[Bound] )
{
    static_assert(Bound == N, "incorrect array size");
}

template 
void check_array_size( const std::array& )
{
    static_assert(Bound == N, "incorrect array size");
}

template 
void check_array_size( ... )
{
    static_assert(N<0, "argument is not an array");
}

template 
void foo(T& param)
{
    check_array_size<3>(param);
    // actual function implementation...
}