c++ - Why is my base class variable undefined at runtime? I'm initializing it from child classes -

i have parent class has variable populate child classes. @ runtime, expression seems never populated. isn't null. it's random thing ide says "expression cannot evaluated." i've stepped through initialization code, , seems initialize correctly. when call variable later @ runtime, throws it's hands in air , says has no idea is.

the base class:

namespace events {   class messagereceiver;    class messagejoint   {   public:     messagejoint( ogre::string id, messagereceiver* receiver );       void fireevent( messagereceiver* );      void setdata( boost::any d ){ data = d; }     void setidentifier( ogre::string id ){ identifier = id; }     virtual void handleevent( boost::any ) = 0;      void tunein( messagereceiver* r )     {       listeners.push_back( r );     }      ogre::string getidentifier(){ return identifier; }      messagereceiver*                  owner;     std::vector< messagereceiver* >   listeners;     boost::any                        data;    private:     ogre::string                      identifier;   }; } 

a child class consumes base class:

  class jointclosemenu : public events::messagejoint   {   public:     static const ogre::string cjointclosemenuid;     jointclosemenu( events::messagereceiver* receiver ) : events::messagejoint( cjointclosemenuid, receiver ){}     void handleevent( boost::any ); #define jointclosemenuname ogre::string("jointclosemenu")   }; 

here's how i'm initializing it. can see i'm setting value of identifier twice!

events::messagejoint::messagejoint( ogre::string id, messagereceiver* receiver )       : identifier( id ), owner(receiver), data( 0 ) { setidentifier( id ); } 

and here's function blows up. goes in messagejoint::getidentifier, , inside there, finds identifier not valid memory address. ide says expression cannot evaluated:

void events::messagejoint::fireevent( messagereceiver* ) {   ogre::string blah = getidentifier(); //<--kaboom!!!!   message m( from->getmyaddress(), owner->getmyaddress(), getidentifier(), &data );    eventmanager::getinstance()->messagedispatch( m );   //} } 

i forgot explain how i'm initializing cjointclosemenuid. in implementation file jointclosemenu class, initialize name of string so:

const ogre::string cjointclosemenuid; 

so figured out problem was. classes fine. accessor using reach container passing value, not reference. so, add instances container via accessor, , discarded when copy of container went out of scope. when code got around attempting use instance of class, had been destructed. doh!