extern DELPHI_PACKAGE TVarDispProc VarDispProc;
Provides the support for IDispatch-based Automation.
In Delphi, VarDispProc points to a routine that is called to execute methods (or access properties) of an interface that is assigned to a Variant. The Variants unit assigns a procedure that generates error 222 or raises an EVariantDispatchError exception. The ComObj unit reassigns this variable to a procedure that generates the appropriate COM IDispatch calls.
To control how Variants execute methods when they have a value that is an interface, assign your own procedure to VarDispProc.