diff --git a/cmd/mem.c b/cmd/mem.c
index 56e1d07..1d4f2ba 100644
--- a/cmd/mem.c
+++ b/cmd/mem.c
@@ -393,7 +393,7 @@
 		 * Defaults to long if no or incorrect specification.
 		 */
 		size = cmd_get_data_size(argv[0], 4);
-		if (size < 0 && size != -2 /* string */)
+		if (size < 0 && size != CMD_DATA_SIZE_STR)
 			return 1;
 
 		argc--;