diff --git a/Include/bytesobject.h b/Include/bytesobject.h
index f1e01d1..12ecf64 100644
--- a/Include/bytesobject.h
+++ b/Include/bytesobject.h
@@ -21,6 +21,7 @@
 /* Object layout */
 typedef struct {
     PyObject_VAR_HEAD
+    int ob_exports; /* how many buffer exports */
     Py_ssize_t ob_alloc; /* How many bytes allocated */
     char *ob_bytes;
 } PyBytesObject;