Description:
------------
The description of the 'length' parameter says "If length is given and is 
positive, then the sequence will have that many elements in it.". This is only 
true if there are that many elements. If the array is shorter than that, the 
sequence will not be forcibly extended; instead it will have as many elements as 
could be extracted from the array.

Test script:
---------------
var_dump( array_slice( array(1, 2, 3), 0, 5 ) );


Expected result:
----------------
array (
  0 => 1,
  1 => 2,
  2 => 3,
  3 => null,
  4 => null,
)

Actual result:
--------------
array (
  0 => 1,
  1 => 2,
  2 => 3,
)