c++ - Casting Pointer of Stack Objects -

i'm building messaging queue , have 2 types of messages 1 uses template class.

class message { public:     message() : m_imessagetype( message_undefined ) {}     message( int imessagetype ) : m_imessagetype( imessagetype ) {}     int gettype() { return m_imessagetype; }     void settype( int imessagetype ) { m_imessagetype = imessagetype; } private:     int m_imessagetype; }  template<typename t> class datamessage: public message { public:     datamessage() : message(), m_odata( t() ) {}     datamessage( int imessagetype, t odata ) : message( imessagetype ), m_odata( odata ) {}     t getdata() { return m_odata; }     void setdata( t odata ) { m_odata = odata; } } 

which allows me send messages this

message tomessage( message_get_name ); datamessage<std::string> frommessage(); messenger::getmessenger()->sendmessage( &tomessage, &frommessage, consumer ); std::cout << "consumer name: " << frommessage.getdata() << std::endl; 

however, leads me doing type casting while handling messages internally (casting message appropriate datamessage<std::string> frommessage in above code). 1 of consumers might this:

class receiver { public:     receiver() { messenger::register( receiver, ); }     handlemessage( message* pin, message* pout ) {         // ignoring usual checking message type         (static_cast<datamessage<std::string>*>( pout ))->setdata( "consumer1" );     } 

is safe cast pointer if points object on stack of calling method?

if try following code (which wrong)

message tomessage( message_get_name ); message frommessage; // consumer going try , cast datamessage<std::string> messenger::getmessenger()->sendmessage( &tomessage, &frommessage, consumer ); 

i don't segfaults or errors. going horribly wrong , it'll creep later during execution?

you’re asking 2 questions here.

is safe cast pointer if points object on stack of calling method?

yes, safe. doesn’t matter object lives long it’s of type cast to.

however, design static_cast not style. dynamic_cast @ least return null pointer if object not of supplied type.

is going horribly wrong , it'll creep later during execution?

yes. casted message datamessage. that’s undefined behavior. possibly you’ll end reading whatever happens on stack after end of message object.