Formal arguments of an imported function can be
specified as open arrays. A formal argument is an open array when a range of
one or more of its dimensions, packed or unpacked, is unspecified (denoted by using empty square brackets ([])). An open array is like a
multi-dimensional dynamic array formal in both packed and unpacked dimensions,
and is thus denoted using the same syntax as dynamic arrays, using [] to denote
an open dimension.. This is solely a relaxation of the argument-matching
rules. An actual argument shall match the formal one regardless of the range(s)
for its corresponding dimension(s), which facilitates writing generalized code
that can handle SystemVerilog arrays of different sizes. See Section 26.4.6.1.