sub query_users { my ( $self, $filename ) = @_; my $func = import_api( 'advapi32', 'QueryUsersOnEncryptedFile', 'PP', 'N' ); die "Could not import API QueryUsersOnEncryptedFile: $!" unless defined $func; $filename = make_unicode( File::Spec->canonpath($filename) ); my $ptr = " " x 4; # 4 == sizeof(void*) my $result = $func->Call( "$filename", $ptr ); print "result: $result\n"; return undef if $result; my $address = unpack( "L*", $ptr ); printf("0x%08x\n", $address); }