use strict; # To make sure you use the right package names.
package My_Wrapper;
sub My_get_data 
{ 
    local $x, $y, $z; # I had 'my', but [tilly] is right.
                      # Thats why I said, "I think." here.
    get_data( @_ );
    return ( $x, $y, $z );
}
package My_main
my ( $x, $y, $z ) = My_Wrapper::My_get_data;