How can I use the output of intersect function in my simulink block?

I have a Matlab function block that contains the following code:

function b = fcn(b1, b2)
coder.extrinsic('polyshape');
p1 = polyshape([b1(1) b1(2);b1(3) b1(4);b1(5) b1(6);b1(7) b1(8)]);
p2 = polyshape([b2(1) b2(2);b2(3) b2(4);b2(5) b2(6);b2(7) b2(8)]);
p3 = intersect(p1, p2);
b = p3.NumRegions;
end

I get the error (Attempt to extract field 'NumRegions' from 'mxArray'). How can I get the value of this field?

Answer 1

[Beshoy Saad]

I created a separate .m file containing this code and called it extrinsically from here.