6.2. igraph_es_adj — Adjacent edges of a vertex.

int igraph_es_adj(igraph_es_t *es, 
		  igraph_integer_t vid, igraph_neimode_t mode);

Arguments:

`es`:	Pointer to an uninitialized edge selector object.
`vid`:	Vertex id, of which the adjacent edges will be selected.
`mode`:	Constant giving the type of the adjacent edges to select. This is ignored for undirected graphs. Possible values: `IGRAPH_OUT`, outgoing edges `IGRAPH_IN`, incoming edges `IGRAPH_ALL`, all edges

Returns:

Error code.

Time complexity: O(1).