lb: bugfix - never skip active pipe when sending msg

src/lb.cpp

@@ -46,8 +46,11 @@ void zmq::lb_t::detach (writer_t *pipe_)
 {
     //  Remove the pipe from the list; adjust number of active pipes
     //  accordingly.
-    if (pipes.index (pipe_) < active)
+    if (pipes.index (pipe_) < active) {
         active--;
+        if (current == active)
+            current = 0;
+    }
     pipes.erase (pipe_);
 }
 
@@ -55,6 +58,8 @@ void zmq::lb_t::kill (writer_t *pipe_)
 {
     //  Move the pipe to the list of inactive pipes.
     active--;
+    if (current == active)
+        current = 0;
     pipes.swap (pipes.index (pipe_), active);
 }
 
@@ -73,11 +78,6 @@ int zmq::lb_t::send (zmq_msg_t *msg_, int flags_)
         return -1;
     }
 
-    //  Move to the next pipe (load-balancing).
-    current++;
-    if (current >= active)
-        current = 0;
-
     //  TODO: Implement this once queue limits are in-place.
     zmq_assert (pipes [current]->check_write (zmq_msg_size (msg_)));
 
@@ -89,6 +89,11 @@ int zmq::lb_t::send (zmq_msg_t *msg_, int flags_)
     int rc = zmq_msg_init (msg_);
     zmq_assert (rc == 0);
 
+    //  Move to the next pipe (load-balancing).
+    current++;
+    if (current >= active)
+        current = 0;
+
     return 0;
 }