synchronisation problem fixed in ctx_t

src/ctx.cpp

@@ -108,8 +108,10 @@ int zmq::ctx_t::terminate ()
 {
     //  First send stop command to sockets so that any
     //  blocking calls are interrupted.
+    slot_sync.lock ();
     for (sockets_t::size_type i = 0; i != sockets.size (); i++)
         sockets [i]->stop ();
+    slot_sync.unlock ();
 
     //  Close the logging infrastructure.
     log_sync.lock ();

src/zmq_init.cpp

@@ -139,7 +139,10 @@ void zmq::zmq_init_t::finalise_initialisation ()
     if (sent && received) {
 
         //  If we know what session we belong to, it's easy, just send the
-        //  engine to that session and destroy the init object.
+        //  engine to that session and destroy the init object. Note that we
+        //  know about the session only if this object is owned by it. Thus,
+        //  lifetime of this object in contained in the lifetime of the session
+        //  so the pointer cannot become invalid without notice.
         if (session) {
             engine->unplug ();
             send_attach (session, engine, peer_identity, true);