Sets the parent widget of the widget.
In contrast to [method@Gtk.Widget.set_parent], this function inserts this at a specific position into
the list of children of the parent widget.
It will be placed before next_sibling, or at the end if next_sibling is `NULL`.
After calling this function, `gtk_widget_get_next_sibling (widget)` will return next_sibling.
If parent is already set as the parent widget of this, this function can also be used to
reorder this in the child widget list of parent.
This function is primarily meant for widget implementations; if you are just using a widget, you *must* use its own API for adding children.
| this |
a widget |
| parent |
the parent widget to insert this into |
| next_sibling |
the new next sibling of this |