Problem: unreachable code around socket_base_t::add/remove_signaler

Solution: replaced by assertion

src/socket_base.cpp

@@ -487,32 +487,20 @@ int zmq::socket_base_t::leave (const char *group_)
     return rc;
 }
 
-int zmq::socket_base_t::add_signaler (signaler_t *s_)
+void zmq::socket_base_t::add_signaler (signaler_t *s_)
 {
-    scoped_optional_lock_t sync_lock (thread_safe ? &sync : NULL);
-
-    if (!thread_safe) {
-        errno = EINVAL;
-        return -1;
-    }
+    zmq_assert (thread_safe);
 
+    scoped_lock_t sync_lock (sync);
     ((mailbox_safe_t *) mailbox)->add_signaler (s_);
-
-    return 0;
 }
 
-int zmq::socket_base_t::remove_signaler (signaler_t *s_)
+void zmq::socket_base_t::remove_signaler (signaler_t *s_)
 {
-    scoped_optional_lock_t sync_lock (thread_safe ? &sync : NULL);
-
-    if (!thread_safe) {
-        errno = EINVAL;
-        return -1;
-    }
+    zmq_assert (thread_safe);
 
+    scoped_lock_t sync_lock (sync);
     ((mailbox_safe_t *) mailbox)->remove_signaler (s_);
-
-    return 0;
 }
 
 int zmq::socket_base_t::bind (const char *addr_)

src/socket_base.hpp

@@ -86,8 +86,8 @@ class socket_base_t : public own_t,
     int term_endpoint (const char *addr_);
     int send (zmq::msg_t *msg_, int flags_);
     int recv (zmq::msg_t *msg_, int flags_);
-    int add_signaler (signaler_t *s);
-    int remove_signaler (signaler_t *s);
+    void add_signaler (signaler_t *s);
+    void remove_signaler (signaler_t *s);
     int close ();
 
     //  These functions are used by the polling mechanism to determine

src/socket_poller.cpp

@@ -130,8 +130,7 @@ int zmq::socket_poller_t::add (socket_base_t *socket_,
             }
         }
 
-        rc = socket_->add_signaler (signaler);
-        zmq_assert (rc == 0);
+        socket_->add_signaler (signaler);
     }
 
     item_t item = {