child.path to a path relative to filter. That is, child.path
points to a path in the child model. The rerturned path will point to the
same row in the filtered model. If child.path isn't a valid path on the
child model or points to a row which is not visible in filter, then NULL
is returned.gtkTreeModelFilterConvertChildPathToPath(object, child.path)objectchild.pathGtkTreePath to convert.GtkTreePath] A newly allocated GtkTreePath, or NULL.