insertBefore
Inserts a new row before @sibling. If @sibling is null, then the row will be appended to @parent ’s children. If @parent and @sibling are null, then the row will be appended to the toplevel. If both @sibling and @parent are set, then @parent must be the parent of @sibling. When @sibling is set,
Parameters
iter
An unset GtkTreeIter
to set to the new row
parent
A valid GtkTreeIter
sibling
A valid GtkTreeIter