WIP: Socket migration between threads, new zmq_close() semantics

Sockets may now be migrated between OS threads; sockets may not be used by
more than one thread at any time. To migrate a socket to another thread the
caller must ensure that a full memory barrier is called before using the
socket from the target thread.

The new zmq_close() semantics implement the behaviour discussed at:

http://lists.zeromq.org/pipermail/zeromq-dev/2010-July/004244.html

Specifically, zmq_close() is now deterministic and while it still returns
immediately, it does not discard any data that may still be queued for
sending. Further, zmq_term() will now block until all outstanding data has
been sent.

TODO: Many bugs have been introduced, needs testing. Further, SO_LINGER or
an equivalent mechanism (possibly a configurable timeout to zmq_term())
needs to be implemented.

1 files changed, 8 insertions, 2 deletions

diff --git a/src/owned.cpp b/src/owned.cpp
index d6be444..7d1cf5e 100644
--- a/src/owned.cpp
+++ b/src/owned.cpp
@@ -35,7 +35,7 @@ zmq::owned_t::~owned_t ()
 
 void zmq::owned_t::inc_seqnum ()
 {
-    //  NB: This function may be called from a different thread!
+    //  This function may be called from a different thread!
     sent_seqnum.add (1);
 }
 
@@ -62,10 +62,16 @@ void zmq::owned_t::finalise ()
 {
     //  If termination request was already received and there are no more
     //  commands to wait for, terminate the object.
-    if (shutting_down && processed_seqnum == sent_seqnum.get ()) {
+    if (shutting_down && processed_seqnum == sent_seqnum.get ()
+          && is_terminable ()) {
         process_unplug ();
         send_term_ack (owner);
         delete this;
     }
 }
 
+bool zmq::owned_t::is_terminable ()
+{
+    return true;
+}
+