+int def_config (graph_config_t *cfg, const oconfig_item_t *ci);
+
+int def_append (graph_def_t *head, graph_def_t *def);
+
+graph_def_t *def_search (graph_def_t *head, graph_ident_t *ident,
+ const char *ds_name);
+
+_Bool def_matches (graph_def_t *def, graph_ident_t *ident);
+
+int def_foreach (graph_def_t *def, def_callback_t callback, void *user_data);