diff --git a/README.rst b/README.rst
index 30a264d..61cc56c 100644
--- a/README.rst
+++ b/README.rst
@@ -116,6 +116,9 @@ the result, or ignoring it. The latter two methods return the number of elements
 in the upcoming container, so that each element in an array, or key-value pair
 in a map, can be unpacked or skipped individually.
 
+Warning: these methods raise ``StopIteration`` when called at the end of the
+stream. Unless caught, this may silently break an iteration.
+
 Each of these methods may optionally write the packed data it reads to a
 callback function: