diff --git a/Modules/cStringIO.c b/Modules/cStringIO.c
index 1251c1d..64e2146 100644
--- a/Modules/cStringIO.c
+++ b/Modules/cStringIO.c
@@ -566,8 +566,7 @@
 
 static PyObject *
 I_close(Iobject *self, PyObject *unused) {
-        Py_XDECREF(self->pbuf);
-        self->pbuf = NULL;
+        Py_CLEAR(self->pbuf);
         self->buf = NULL;
 
         self->pos = self->string_size = 0;