invalidIUnknown MDA
The invalidIUnknown managed debugging assistant (MDA) is activated when an invalid IUnknown pointer is passed to managed code from native code. The IUnknown fails to return success when queried for the IUnknown interface.
Symptoms
An unexpected error occurs when marshaling a COM interface pointer during argument marshaling.
Cause
An incorrect QueryInterface implementation on the COM interface passed to the CLR.
Resolution
Correct the QueryInterface implementation.
Effect on the Runtime
This MDA has no effect on the CLR.
Output
The description of the error.
Configuration
<mdaConfig>
<assistants>
<invalidIUnknown />
</assistants>
</mdaConfig>
See Also
Concepts
Diagnosing Errors with Managed Debugging Assistants