Sets iter to be the parent of child.
If child is at the toplevel, and doesn’t have a parent, then iter is set to an invalid iterator and
false is returned. child will remain a valid node after this function has been called.
iter will be initialized before the lookup is performed, so child and iter cannot point to the
same memory location.
| this |
a `GtkTreeModel` |
| iter |
the new `GtkTreeIter` to set to the parent |
| child |
the `GtkTreeIter` |
|
true, if |