Fixed Length Arrays

Can somebody tell me how to define a fixed length array? The manual is
pretty sparse on arrays.

I'm trying to create a fixed length boolean array by using:

CREATE TABLE test (apple boolean[5]);

This creates the array, but it is not fixed in length. Inserting and
retrieving larger arrays (greater than 5) seems to work. Am I not
seeing how this is supposed to work??

Any enlightenment would be appreciated. Thanks.

Arthur