Re: Trouble figuring out DirectCall interface

I'm getting a Memory Access Violation on the GetFunctionAddress call 
itself. I have no doubt that I'm doing something wrong but I have 
failed to see it so far. 


--- In [email protected], Roger Corman <roger@c...> wrote:
> Are you saying that the call to GetFunctionAddress() returns an 
error code? Or that it crashes with a memory access violation at 
that point?
> 
> The IDE makes quite a bit of use of DirectCall.
> 
> Have you defined your callback function in the win32 package? 

Yes, in :Win32

Does it need to be exported as well? I thought I had tried that 
already.

> 
> Also, once you get the function pointer back successfully, the 
defun-direct-callback macro will assume the function is :c linkage 
by default, you need to use :pascal linkage if you are going to 
declare it as __stdcall. This would probably cause an access 
violation.

I understand the defun-direct-callback to be for pascal linkage and 
the defun-direct-c-callback for C linkage, correct?

calling convention
------------------

pascal = __stdcall
C      = __cdecl

Right?


quizzically,
 Wayne Rogers


> 
> 
> At 04:56 PM 9/30/2003, you wrote:
> 
> >Has anyone gotten the call back functions to work via the 
> >DirectCall interface? I keep getting a Memory access violation. 
> >
> >I am trying to do something like this:
> >
> >(defun-direct-callback add2numbers ((a long)(b long))
> >    (+ a b))
> >
> >
> >(save-image "math.img")
> >
> >// SimpleMath.h
> >
> >.
> >.
> >.
> >typedef long (__stdcall *pfadder)(long, long);
> >
> >pfadder m_pfAdder;
> >
> >// SimleMath.cpp
> >
> >
> >STDMETHODIMP CSimpleMath::add(long a, long b, long* c)
> >{
> >        if(!m_pfAdder)
> >        {
> >        
> >                HRESULT hr = m_iLispCall->GetFunctionAddress
> >(L"ADD2NUMBERS",L"WIN32",(LPVOID*)&m_pfAdder);
> >        }
> >
> >        *c = m_pfAdder(a, b);
> >        //*c = a + b;
> >        return S_OK;
> >}
> >
> >
> >//end
> >The initialize and the BlessThread all return S_OK, the 
> >connectionpoint to ICormanLispTextOutput is successful, corman 
text 
> >output flows through, but it errors out 
> >on the GetFunctionAddress call. Any ideas out there?
> >
> >
> >
> >
> >
> >To unsubscribe from this group, send an email to:
> >[email protected]
> >
> > 
> >
> >Your use of Yahoo! Groups is subject to 
http://docs.yahoo.com/info/terms/


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