-void open_graph PARAMS ((struct obstack *os));
-void output_graph PARAMS ((graph_t *graph, struct obstack *os));
-void close_graph PARAMS ((graph_t *graph, struct obstack *os));
+void open_graph PARAMS ((FILE *fout));
+void output_graph PARAMS ((graph_t *graph, FILE *fout));
+void close_graph PARAMS ((graph_t *graph, FILE *fout));