my $tree = new_tree();

print node_count($tree), "\n";
__END__
__C__

typedef struct {
      int  count;
} Tree;


SV* new_tree () {
    Tree* tree;
    tree.count = 0;
    /* return tree some how */
}

int node_count (SV* tree) {
    /* get back at tree some how */
    return tree.count;
}