diff --git a/src/pgm_receiver.cpp b/src/pgm_receiver.cpp
index 2a9dc8b6..c556368b 100644
--- a/src/pgm_receiver.cpp
+++ b/src/pgm_receiver.cpp
@@ -288,7 +288,7 @@ void zmq::pgm_receiver_t::drop_subscriptions ()
 {
     msg_t msg;
     msg.init ();
-    while (session->pull_msg (&msg))
+    while (session->pull_msg (&msg) == 0)
         msg.close ();
 }