On page 911 he says: "Note that the variable VERSION_NUMBER is used exclusively by the IMPLEMENT_SERIAL() macros in the shape classes, so you could delete it from the OurConstants.h file used in the Sketcher program".

However, when I do delete it, it doesn't compile, because it's used in Elements.cpp:

// Elements.cpp : implementation file
//

#include "stdafx.h"

#include "Elements.h"
#include <math.h>
#include "OurConstants.h"

IMPLEMENT_SERIAL(CElement, CObject, VERSION_NUMBER)
IMPLEMENT_SERIAL(CLine, CElement, VERSION_NUMBER)
IMPLEMENT_SERIAL(CRectangle, CElement, VERSION_NUMBER)
IMPLEMENT_SERIAL(CCircle, CElement, VERSION_NUMBER)
IMPLEMENT_SERIAL(CCurve, CElement, VERSION_NUMBER)
IMPLEMENT_SERIAL(CText, CElement, VERSION_NUMBER)

...

So what gives?

Dan Crossley

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Dan Crossley

Hi Dan,

You've probably worked this out by now, but I thought I'd post a few words just in case.

It's been a while since I worked through the sketcher program, but reading that paragraph on page 911 it seems that in the initial creation of the .dll project Ivor's telling you to create a copy of the 'Our Constants.h' file to reside in the .dll project. Once you've done that you'll have one copy of the header file in the .dll project and a duplicate (for the time being) in the Sketcher project.

I think what Ivor is saying is that since the VERSION_NUMBER constant is only used in the IMPLEMENT_SERIAL macro, which itself is only used in the .dll, you can remove the VERSION_NUMBER declaration in the original 'Our Constants.h' file in the Sketcher project. As you've found, you can't delete it from the header file in the .dll project because it's still needed there. But in the Sketcher project it's no longer required.

Hope that helps.

Dan

Dan6,

Thanks for clearing that up.

Dan Crossley