Ogre Forums

Posted: **Thu Jun 22, 2006 5:00 pm**

I'm trying to export a class for a dll that has a std::list member variable, but the compiler gives me this warning:

(32) : warning C4251: 'IEventReceiver::mPendingEvents' : class 'std::list<_Ty>' needs to have dll-interface to be used by clients of class 'IEventReceiver'

The code looks like this:

Code: Select all

class EGExport IEventReceiver
{
public:
	IEventReceiver();
	virtual ~IEventReceiver();

private:
	IEventReceiver( IEventReceiver const& );

public:
	void receiveEvent( IEvent *event );
	virtual void handleEvent( IEvent *event ) = 0;
	void handleAllEvents();

	virtual void subscribeToEvents() = 0;
	void unsubscribeFromAllEvents();

private:
        // compiler is complaining about the line below
	EventList mPendingEvents;	
};

I've looked through Ogre's code and though I can see that Ogre is successfully doing this, I can't figure out how.

Any help would be much appreciated.

Edit:
Here's the typdef for EventList

Code: Select all

typedef std::list<IEvent*> EventList;

Posted: **Thu Jun 22, 2006 5:09 pm**

Just a guess: Maybe you're not using multithreaded dll runtime libs? Meaning not /MD or /MDd? If so change it accordingly.

Posted: **Thu Jun 22, 2006 5:18 pm**

Ogre specifically disables that warning, that is how Ogre does it

Posted: **Thu Jun 22, 2006 5:29 pm**

Ah, yeah, so it does. Thanks for the speedy response guys.

Posted: **Wed Jun 28, 2006 9:18 pm**

I'm using the intel-compiler (just wanted to play around a bit with it)
and I think having the same problem (different errorcode though
because of the compiler)....
Although the intel-compilers marks it as an error, not a warning...

Does anyone know if I can do something simular to 'make the
problem go away' - or is there a 'correct' way to solve it?

---

error #1744: field of class type without a DLL interface used in
a class with a DLL interface

class _MyExport Derived : public Base
{
private:
std::vector <char> buf; //< Error 1744 on this line
}

Posted: **Wed Jun 28, 2006 11:33 pm**

You should do some google searching, I have seen a workaround, where the template can be exported too. I suggest you search using the Windows warning number, you will find more specific hits on the matter. However, the workaround was not pretty, and only mostly worked IIRC.

Posted: **Thu Jun 29, 2006 12:05 am**

Do a search for "C4251" and "DLL-interface" (or similar).
I saw some workarounds @ MSDN.

Posted: **Thu Jun 29, 2006 12:55 am**

http://www.unknownroad.com/rtfm/VisualS ... C4251.html

This is what you're looking for:

Code: Select all

struct SMessage{
	std::string code;
	std::vector<SMessageDesc> messages;
};
// The following lines are required to properly export std::vector from a DLL
template class DLL_EXPORT std::allocator<SMessage>;
template class DLL_EXPORT std::vector<SMessage, std::allocator<SMessage> >;
std::vector<SMessage> mMessages;

If only I could get back that night spent searching for this answer...

Posted: **Wed Jul 12, 2006 11:28 pm**

Thanks guys!

Going to try that out tomorrow!

as a sidenote, I did google on it with variations on the (intel) error message,
but it didn't show up with any solutions - didn't cross my mind
to google on the microsoft message (because in vc7 it's working) lol

Ogre Forums

Warning C4251 using STL container member in class in DLL

Warning C4251 using STL container member in class in DLL