Re: Heap problems after FreeLibrary

From:

"Carl Daniel [VC++ MVP]" <cpdaniel_remove_this_and_nospam@mvps.org.nospam>

Newsgroups:

microsoft.public.vc.language

Date:

Mon, 15 May 2006 14:36:14 -0700

Message-ID:

<eQRbjeGeGHA.2068@TK2MSFTNGP02.phx.gbl>

"Stefan" <punkman@uboot.com> wrote in message
news:1147724910.793805.61170@y43g2000cwc.googlegroups.com...

Ok, here's a clarification:

--
EXE code:

SomeSharedDataStucture *pData = new SomeSharedDataStucture;

HINSTANCE hLibrary = LoadLibrary("mylib.dll");
SomeAPIFunctionType someAPIFunction = (SomeAPIFunctionType)
GetProcAddress(hLibrary,"someAPIFunction");
someAPIFunction(pData);
FreeLibrary(hLibrary);

delete pData->pObject; // <- fails, but works if FreeLibrary is
commented out

--
DLL code:

extern "C" __declspec(dllexport) void
someAPIFunction(SomeSharedDataStructure *pData)
{
pData->pObject = new SomeObject();
}

Where's the code for SomeObject? If it's in the DLL, then you're unloading
the code for the destructor and then attempting to call it. It makes no
difference how (or even if) the class is linked with MFC or the CRT. Unless
the class has a trivial destructor (no virtual functions, no members of
class type), then code IS generated for a destructor whether you wrote a
destructor explicitly or not.

-cd