fixed compiler error

source/RobotAPI/components/units/ForceTorqueObserver.cpp

@@ -74,9 +74,9 @@ void ForceTorqueObserver::offerValue(std::string nodeName, const std::string &ty
     FramedVector3Ptr vec = FramedVector3Ptr::dynamicCast(value);
 
     DataFieldIdentifierPtr id;
-    if(type ==FORCES_STRING)
+    if(type =="forces")
         id = getForceDatafieldId(nodeName, vec->frame);
-    else if(type == TORQUES_STRING)
+    else if(type == "torques")
         id = getTorqueDatafieldId(nodeName, vec->frame);
     else
         throw LocalException() << "Unknown sensor type: " << type;
@@ -112,12 +112,12 @@ void armarx::ForceTorqueObserver::reportSensorValues(const std::string &sensorNo
 
     if(forces)
     {
-        std::string type = FORCES_STRING;
+        std::string type = "forces";
         offerValue(sensorNodeName, type, forces);
     }
     if(torques)
     {
-        std::string type = TORQUES_STRING;
+        std::string type = "torques";
         offerValue(sensorNodeName, type, torques);
     }
 }
@@ -148,7 +148,7 @@ DataFieldIdentifierPtr ForceTorqueObserver::getForceDatafieldId(const std::strin
         channelName = nodeName;
     else
         channelName = nodeName + "_" + frame;
-    std::string datafieldName = FORCES_STRING;
+    std::string datafieldName = "forces";
     if(!existsChannel(channelName))
         throw UserException("No sensor for node '" + nodeName + "'available: channel " + channelName);
     if(!existsDataField(channelName, datafieldName))
@@ -164,7 +164,7 @@ DataFieldIdentifierPtr ForceTorqueObserver::getTorqueDatafieldId(const std::stri
         channelName = nodeName;
     else
         channelName = nodeName + "_" + frame;
-    std::string datafieldName = TORQUES_STRING;
+    std::string datafieldName = "torques";
     DataFieldIdentifierPtr id = new DataFieldIdentifier(getName(), channelName, datafieldName);
     return id;
 }

source/RobotAPI/components/units/ForceTorqueObserver.h

@@ -44,8 +44,11 @@ namespace armarx
          */
         virtual PropertyDefinitionsPtr createPropertyDefinitions();
 
-        const std::string FORCES_STRING = "forces";
-        const std::string TORQUES_STRING = "torques";
+        // DOES NOT COMPILE:
+        // sorry, unimplemented: non-static data member initializers
+        // error: in-class initialization of static data member ‘FORCES_STRING’ of non-literal type
+        //const std::string FORCES_STRING = "forces";
+        //const std::string TORQUES_STRING = "torques";
     private:
         armarx::Mutex dataMutex;
         std::string topicName;