fix comments.

* src/graphviz.h: Add missing license notice.
	Document.
(cherry picked from commit c7b5c7fd06)

ChangeLog

@@ -1,3 +1,9 @@
+2010-03-30  Akim Demaille  <demaille@gostai.com>
+
+	fix comments.
+	* src/graphviz.h: Add missing license notice.
+	Document.
+
 2010-03-25  Akim Demaille  <demaille@gostai.com>
 
 	tests: fix 250: parse.error=verbose overflow.

src/graphviz.h

@@ -1,7 +1,50 @@
-#include <stdbool.h>
+/* Output Graphviz specification of a state machine generated by Bison.
 
+   Copyright (C) 2006, 2010 Free Software Foundation, Inc.
+
+   This file is part of Bison, the GNU Compiler Compiler.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* Written by Paul Eggert and Satya Kiran Popuri.  */
+
+#ifndef GRAPHVIZ_H_
+# define GRAPHVIZ_H_
+# include <stdbool.h>
+
+/// Begin a Dot graph.
+/// \param fout   output stream.
 void start_graph (FILE *fout);
+
+/// Output a Dot node.
+/// \param id     identifier of the node
+/// \param label  human readable label of the node (no Dot escaping needed).
+/// \param fout   output stream.
 void output_node (int id, char const *label, FILE *fout);
+
+/// Output a Dot edge.
+/// \param source       id of the source node
+/// \param destination  id of the target node
+/// \param label        human readable label of the edge
+///                     (no Dot escaping needed).  Can be 0.
+/// \param style        Dot style of the edge (e.g., "dotted" or "solid").
+/// \param fout         output stream.
 void output_edge (int source, int destination, char const *label,
 		  char const *style, FILE *fout);
+
+/// End a Dot graph.
+/// \param fout  output stream.
 void finish_graph (FILE *fout);
+
+#endif /* ! GRAPHVIZ_H_ */