No, the documentation that you quote is talking about the third argument to the new() method, which certain shouldn't contain packed double values. It is talking about the argument [P, I] in the code above.

The array of doubles is an argument to the C API being accessed and so gets passed in via the Call() method.

Note that I avoid using the style found in the Win32::API documentation and would rewrite the code as:     my $obj= Win32::API->new( "dll", "Function", [qw( P I )], 'I' ); so that I could use strict with it.

        - tye (but my friends call me "Tye")