Re: Stack prob. Setting callback in native dll.

There is one more step. You must use the apply modification option to the
delegate( i.e., modopt) using ildasm
see the following for details:
http://groups.google.com/group/microsoft.public.dotnet.framework.interop/msg/eaf7bd2549f5a3a3


dlbriggs" <dlbriggs1729@xxxxxxxxx> wrote in message
news:1150897040.463426.66240@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Thanks fro the replay.
I have tried setting the CallingConvention to Cdecl, SdCall and WinApi.
None of this worked. And the thing is I have other calls into the dll
and they work OK.


Michael Phillips, Jr. wrote:
You may want to set the calling convention if it is not the default
WINAPI( StdCall ):

[DllImport("w32dll.dll", CallingConvention=CallingConvention.Cdecl)]
static void dllSetCallFp( void (*aFp)(void*) );


<dlbriggs1729@xxxxxxxxx> wrote in message
news:1150837798.880414.310440@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
I have a 3th party dll writen in C. I have no problem calling most
functions in the dll from the managed code. But there is a function
that take a function pointer for setting a callback function that I am
having problems with.
I have the following code:

First in a wrapper class

[DllImport("w32dll.dll")] static void dllSetCallFp( void
(*aFp)(void*) );

Then in seperate class.

delegate void funDelegate(void*);
typedef void ( *FUNPT)(void*);
funDelegate ^ fp = gcnew funDelegate(MFun);
pin_ptr<funDelegate^> pp = &fp;
IntPtr ip = Marshal::GetFunctionPointerForDelegate(fp);
FUNPT cb = static_cast<FUNPT>(ip.ToPointer());
Wrapper::dllSetCallFp(cb);

MFun is just a test function.

void Client::MFun(void* pV)
{
int i = 9;
}

The problem is I can debug into the calling of MFun but when I return I
get the following errors
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.
Then
'FatalExecutionEngineError'




.

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