Improve comment.

diff --git a/src/data/datasheet.c b/src/data/datasheet.c
index 1fc1e98b08aba877620733f90a12a225a0be4f36..63db4f36d38356293cd93d60b8e40db7408f3519 100644 (file)
--- a/src/data/datasheet.c
+++ b/src/data/datasheet.c
@@ -150,7 +150,8 @@ static bool rw_case (struct datasheet *ds, enum rw_op op,
 /* Creates and returns a new datasheet.
 
    If READER is nonnull, then the datasheet initially contains
-   the contents of READER. */
+   the contents of READER.  READER become owned by the datasheet
+   and the caller must not directly reference it again. */
 struct datasheet *
 datasheet_create (struct casereader *reader)
 {