Thus the functions imported
to and exported from SystemVerilog have their own
global name space of linkage names, different from compilation-unit
scope $root name space.
26.4.1.2 input,
output and inout and output arguments
Imported functions can have input, output, and inout and output arguments. The
formal input arguments shall
not be modified. If such arguments are changed within a function, the changes
shall not be visible outside the function; the actual arguments shall not be
changed.
The imported function shall not assume anything about the initial
values of formal output arguments. The
initial values of output arguments are
undetermined and implementation-dependent.
The imported
function can access the initial value of a formal inout argument. Changes that the imported function makes to a formal inout argument shall be visible
outside the function.