Although the FORTRAN 77 standard prohibits aliasing arguments, the Sun Performance Library allows the programmer to alias two or more arguments as long as all aliased arguments have the same base type and none of the arguments being aliased is an output argument. A real variable and a complex variable have the same base type (real), while a real variable and a double precision variable have different base types. Aliasing arguments having different base types or aliasing any argument with an output argument will produce undefined results at best. It is not even guaranteed that these undefined results will be the same from one run to the next.