+ //read the number of edges
+ char *nedges_str = NULL;
+ read = xbt_getline (&nedges_str, &size, file);
+ if (read == -1)
+ THROWF(system_error, 0, "xbt_getline failed to read the number of edges (errno = %d)", errno);
+ int nedges = atoi (nedges_str);
+ free (nedges_str);
+
+ //read all edges
+ for (i = 0; i < nedges; i++){
+ char *edge_str = NULL, edge_id[200], node_source[200], node_target[200];
+ read = xbt_getline (&edge_str, &size, file);
+ if (read == -1)
+ THROWF(system_error, 0, "xbt_getline failed to read all edges (errno = %d)", errno);
+ sscanf (edge_str, "%s %s %s", edge_id, node_source, node_target);
+ free (edge_str);
+ xbt_str_subst (edge_id, '\n', '\0', 0);
+ xbt_str_subst (node_source, '\n', '\0', 0);
+ xbt_str_subst (node_target, '\n', '\0', 0);
+
+ xbt_node_t source = xbt_dict_get (nodes_dict, node_source);
+ xbt_node_t target = xbt_dict_get (nodes_dict, node_target);
+ xbt_graph_new_edge (ret, source, target, xbt_strdup(edge_id));
+ }
+ xbt_dict_free (&nodes_dict);
+ return ret;