Re: exportdll DLL

From:
"Doug Harrison [MVP]" <dsh@mvps.org>
Newsgroups:
microsoft.public.vc.mfc
Date:
Wed, 26 Jul 2006 23:42:45 -0500
Message-ID:
<bcggc2p27eqhv5bmrdbjj7t1ub2flobp4e@4ax.com>
On 26 Jul 2006 19:33:22 -0700, "Ajay Kalra" <ajaykalra@yahoo.com> wrote:

I dont know how that will happen. If CMetadata is not exported, there
will be a link time failure as the client DLL will not be able to find
the class in any of the libraries its linking against. I guess the only
way it can succeed is if you force a compile (not recommended)
regardless.


I did say I couldn't explain the OP's observation unless one of the two
scenarios I listed applied. :) What I said about "inline" was a bit of a
stretch, since an inline function doesn't really belong to any module; I
guess I thought of it because the header it appears in is considered part
of the module's interface. The virtual function issue is more interesting.
Suppose you have the OP's class CMetaData:

class CMetaData
{
public:

   virtual void f();
};

Per the OP's message, another class X (presumably exported) creates a
CMetaData and returns a pointer to it to another module. Now that other
module can call p->f(), even though CMetaData::f isn't exported. What it
can't do is say p->CMetaData::f(), because that disables the virtual call
mechanism and causes the compiler to bind to f's actual address. So, the
OP's observation could be explained if the CMetaData::GetValue in his
actual code is a virtual function.

--
Doug Harrison
Visual C++ MVP

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