Hi.

I am writing a C# interface to a C++ / C driver for a hardware card and I am
having the following issue when trying to set up a callback function. When
the card generates an event that causes the driver to invoke the callback,
Visual Studio (or the application if running the straight executable)
crashes. Can anyone verify if I am setting the callback function correctly?
Has anyone run into a similar problem when passing delegates to C++ code that
expects a function pointer as input? Thanks.

C# Signature:
[DllImport(libVpbLocation)]
private static extern int vpb_set_event_callback(int handle,
CardCallbackEventHandler CardCallBack, object context);

C++ / C Function signature
int WINAPI vpb_set_event_callback(int handle, void (WINAPI
*event_callback)(VPB_EVENT *e, void *context), void *context)

C# Delegate Definition:
public delegate void CardCallbackEventHandler(ref VpbEvent eventData, object
context);

C# Callback function signature
private void Callback_Event(ref VpbEvent eventData, object context)

C# code that calls the function to set the callback  
...
CardCallbackEventHandler callback = new CardCallbackEventHandler
(Callback_Event);
int RetValue = vpb_set_event_callback(Handle, callback, this);
...

Finally, the VpbEvent object is a struct with a few integer members.