my $foo = undef;
my $bar = Foo::create_bar (\$foo);

##</code><code>##

struct bar*
create_bar(foo)
  struct type_foo* foo
  CODE:
    RETVAL = my_c_create_bar(foo);
  OUTPUT:
    RETVAL

##</code><code>##

TYPEMAP
struct bar* T_OBJECT
struct type_foo* T_OBJECT