diff --git a/include/easycsv.h b/include/easycsv.h
index 1252465..4a25d4f 100644
--- a/include/easycsv.h
+++ b/include/easycsv.h
@@ -167,7 +167,7 @@ easycsv_read_value(const easycsv*,
 /** 
  * Return number of rows 
  * @param[in] constant pointer to easycsv structure 
- * @return number of rows
+ * @return number of rows, -1 if error
  */
 int
 easycsv_print_rows(const easycsv*);
@@ -175,7 +175,7 @@ easycsv_print_rows(const easycsv*);
 /** 
  * Return number of columns
  * @param[in] constant pointer to easycsv structure 
- * @return number of columns
+ * @return number of columns, -1 if error
  */
 int
 easycsv_print_columns(const easycsv*);