casereader: Add const to casereader_peek() and casereader_is_empty().

[pspp] / src / data / casereader.h

diff --git a/src/data/casereader.h b/src/data/casereader.h
index 680e669928331a6ffccea5f72c4392e499f3b825..da4eaa2f3bcdb827a1e41bcfe64cd98b86b7d8e6 100644 (file)
--- a/src/data/casereader.h
+++ b/src/data/casereader.h
@@ -67,8 +67,8 @@ struct casereader *casereader_clone (const struct casereader *);
 struct casereader *casereader_rename (struct casereader *);
 void casereader_swap (struct casereader *, struct casereader *);
 
-struct ccase *casereader_peek (struct casereader *, casenumber);
-bool casereader_is_empty (struct casereader *);
+struct ccase *casereader_peek (const struct casereader *, casenumber);
+bool casereader_is_empty (const struct casereader *);
 
 bool casereader_error (const struct casereader *);
 void casereader_force_error (struct casereader *);