[ADVANCED-DOTNET] P/Invoke question

[Russell McClure]

I am trying to call a C++ function in a regular Win32 DLL with the
following signature:
bool MyFunc
(
    void               **ppSER,
    void               **ppVoid,
    bool                 bSetting
)
The first function is a callback function which I seem to be passing
correctly because it does get invoked.  The second parameter gets passed to
the callback as one of its parameters (defined as void*).
The C++ code that uses this function passes the second parameter as:
(void**)(this)
I am using C# and everything works execpt I don't know what to pass for the
second parameter.  I first defined it as an IntPtr and passed
this.Handle.  Doing that the callback was actually called but on return I
got this error:
"Run-Time Check Failure #0 - The value of ESP was not properly saved across
a function call.  This is usually a result of calling a function declared
with one calling convention with a function pointer declared with a
different calling convention."
I assume that it is the second parameter that is screwing things up since
the first one (void **ppSER) is the callback and it is being invoked and
the third parameter (bool bSetting) is obviously OK.
So my question boils down to: does anyone know the C# equivalent of the C++
(void**)(this)?
Thanks.

Russ