diff --git a/lib/readkey.c b/lib/readkey.c
index 895db8214..1117c30ac 100644
--- a/lib/readkey.c
+++ b/lib/readkey.c
@@ -67,7 +67,7 @@ int read_key(void)
 				esc[i] = getc();
 				if (esc[i++] == '~')
 					break;
-				if (i == 5)
+				if (i == ARRAY_SIZE(esc))
 					return -1;
 			}
 		}