Added test and updated documentation for unbind wild-card * binded socket

doc/zmq_unbind.txt

@@ -20,6 +20,12 @@ argument.
 
 The 'endpoint' argument is as described in linkzmq:zmq_bind[3]
 
+Unbinding wild-card addres from a socket
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+When wild-card `*` 'endpoint' (described in linkzmq:zmq_tcp[7] and 
+linkzmq:zmq_ipc[7]) was used in _zmq_bind()_, the caller should use 
+real 'endpoind' obtained from the ZMQ_LAST_ENDPOINT socket option 
+to unbind this 'endpoint' from a socket.
 
 RETURN VALUE
 ------------
@@ -36,8 +42,8 @@ The 0MQ 'context' associated with the specified 'socket' was terminated.
 The provided 'socket' was invalid.
 
 
-EXAMPLE
--------
+EXAMPLES
+--------
 .Unbind a subscriber socket from a TCP transport
 ----
 /* Create a ZMQ_SUB socket */
@@ -51,6 +57,23 @@ rc = zmq_unbind (socket, "tcp://127.0.0.1:5555");
 assert (rc == 0);
 ----
 
+.Unbind wild-card `*` binded socket
+----
+/* Create a ZMQ_SUB socket */
+void *socket = zmq_socket (context, ZMQ_SUB);
+assert (socket);
+/* Bind it to the system-assigned ephemeral port using a TCP transport */
+rc = zmq_bind (socket, "tcp://127.0.0.1:*");
+assert (rc == 0);
+/* Obtain real endpoint */
+const size_t buf_size = 32;
+char buf[buf_size];
+rc = zmq_getsockopt (socket, ZMQ_LAST_ENDPOINT, buf, (size_t *)&buf_size);
+assert (rc == 0);
+/* Unbind socket by real endpoint */
+rc = zmq_unbind (socket, buf);
+assert (rc == 0);
+----
 
 SEE ALSO
 --------

tests/test_term_endpoint.cpp

@@ -23,8 +23,11 @@ int main (void)
 {
     setup_test_environment();
     int rc;
-    char buf[32];
+    const size_t buf_size = 32;
+    char buf[buf_size];
     const char *ep = "tcp://127.0.0.1:5560";
+    const char *ep_wc_tcp = "tcp://127.0.0.1:*";
+    const char *ep_wc_ipc = "ipc://*";
 
     //  Create infrastructure.
     void *ctx = zmq_ctx_new ();
@@ -100,5 +103,45 @@ int main (void)
     rc = zmq_ctx_term (ctx);
     assert (rc == 0);
 
+    //  Create infrastructure (wild-card binding)
+    ctx = zmq_ctx_new ();
+    assert (ctx);
+    push = zmq_socket (ctx, ZMQ_PUSH);
+    assert (push);
+    rc = zmq_bind (push, ep_wc_tcp);
+    assert (rc == 0);
+    pull = zmq_socket (ctx, ZMQ_PULL);
+    assert (pull);
+    rc = zmq_bind (pull, ep_wc_ipc);
+    assert (rc == 0);
+
+    // Unbind sockets binded by wild-card address
+    rc = zmq_getsockopt (push, ZMQ_LAST_ENDPOINT, buf, (size_t *)&buf_size);
+    assert (rc == 0);
+    rc = zmq_unbind (push, buf);
+    assert (rc == 0);
+    rc = zmq_getsockopt (pull, ZMQ_LAST_ENDPOINT, buf, (size_t *)&buf_size);
+    assert (rc == 0);
+    rc = zmq_unbind (pull, buf);
+    assert (rc == 0);
+
+    //  Create infrastructure (wild-card binding)
+    ctx = zmq_ctx_new ();
+    assert (ctx);
+    push = zmq_socket (ctx, ZMQ_PUSH);
+    assert (push);
+    rc = zmq_bind (push, ep_wc_tcp);
+    assert (rc == 0);
+    pull = zmq_socket (ctx, ZMQ_PULL);
+    assert (pull);
+    rc = zmq_bind (pull, ep_wc_ipc);
+    assert (rc == 0);
+
+    // Sockets binded by wild-card address can't be unbinded by wild-card address
+    rc = zmq_unbind (push, ep_wc_tcp);
+    assert (rc == -1 && zmq_errno () == ENOENT);
+    rc = zmq_unbind (pull, ep_wc_ipc);
+    assert (rc == -1 && zmq_errno () == ENOENT);
+
     return 0;
 }