Handle write calls without a message

If someone includes the Logger into an ApplcationModule and calls writeAll() the Logger variable message will be written. To catch that cases set message empty after calling sendMessage and ignore empty messages in the LoggingModule.

Modules/src/Logging.cc

@@ -55,6 +55,8 @@ void Logger::sendMessage(const std::string& msg, const logging::LogLevel& level)
     }
     message = std::to_string(level) + msg + "\n";
     message.write();
+    // set emtpy message to let the LoggingModule know that someone called writeAll() without sending a message
+    message = "";
   }
   else {
     // only use the buffer until ctk initialized the process variables
@@ -108,16 +110,16 @@ void LoggingModule::mainLoop() {
     id_list[module->msg.getId()] = &(*module);
   }
   auto group = readAnyGroup();
-
+  std::string msg;
+  MessageSource* currentSender;
+  LogLevel level;
+  
   while(1) {
     auto id = group.readAny();
     if(id_list.count(id) == 0){
       throw ChimeraTK::logic_error("Cannot find  element id"
                                      "when updating logging variables.");
     }
-    std::string msg;
-    MessageSource* currentSender;
-    LogLevel level;
     try{
       currentSender = id_list.at(id);
       msg = (std::string)(currentSender->msg);
@@ -125,6 +127,10 @@ void LoggingModule::mainLoop() {
       throw ChimeraTK::logic_error("Cannot find  element id"
                                            "when updating logging variables.");
     }
+    // if message is empty assume someone called writeAll() in a module containing the Logger -> ignore
+    if(msg.empty()){
+      continue;
+    }
     try{
       level = static_cast<LogLevel>(std::strtoul(&msg.at(0),NULL, 0));
     } catch (std::out_of_range &e){