Allow an empty input recipe to the RTDE client

Author: urfeex

src/rtde/rtde_client.cpp

@@ -169,9 +169,16 @@ void RTDEClient::setupCommunication(const size_t max_num_tries, const std::chron
     return;
   }
 
-  setupInputs();
+  if (input_recipe_.size() > 0)
+  {
+    setupInputs();
   if (client_state_ == ClientState::UNINITIALIZED)
     return;
+  }
+  else
+  {
+    writer_.init(0);
+  }
 
   // We finished communication for now
   pipeline_->stop();
@@ -717,4 +724,4 @@ std::vector<std::string> RTDEClient::splitVariableTypes(const std::string& varia
   return result;
 }
 }  // namespace rtde_interface
-}  // namespace urcl
+}  // namespace urcl