Many thanks for your insight on this matter. As you suggested, I've implemented a shim and it's working as expected :-)
Thanks to all for your help!
-- Ron
On Wednesday, January 28, 2004, at 10:19 PM, Keith Hill wrote:
On Tue, 27 Jan 2004 16:29:46 -0800, [EMAIL PROTECTED] wrote:// Callback function pointer def
typedef unsigned (__cdecl *ioCallbackPtr)(unsigned char *buffer,
unsigned long count, unsigned long filePtr);
<snip>
If the initial function expects the callback to be called with the cdecl
calling convention, can that be specified in the C# declaration for the
callback?
Be aware that CallingConvention enum used by the DllImport attribute only
specifies the calling convention when calling from managed code to
unmanaged code and not the other way around. Your callback function
prototype indicates that the unmanaged code expects to call the calback
function using CDECL. When you pass a callback function ptr via a
Delegate to unmanaged code, the CLR *always* expects that function to be
called using the stdcall calling convention. There is no attribute to
modify this behavior. Hence I believe you will need to go the MC++ shim
approach I mentioned before. BTW, you can try this without the shim and
it might seem to work but just remember. In this scenario, both sides
will clean up the stack and that will cause some weird behavior (most
likely a crash).
-- Keith
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