How to show name attributes when plot a joined graph object with multiple name attributes

Hello. If a joined new object is generated by graph.disjoint.union(multi_graph_obj). Each artifact of the joined igraph objects got a name attribute by set.graph.attribute function. Example as follows:

g1 = graph.ring(10)
g1 = set.graph.attribute(g1, 'name','A')
g2 =,mode="undirected")
g2 = set.graph.attribute(g2, 'name','B')
g3 =,mode="undirected")
g3 = set.graph.attribute(g3, 'name','c')

## then joint together to a new igraph object
g = graph.disjoint.union(g1, g2, g3)
plot(g) ## I would like to show the name attributes of each igraph artifacts automatically

There are more then 30 artifacts in the graph object, is there a solution to automatically show the names in then center (or below, left, above, right ) for each of the subObject of graph g? Thank you.