Header File: dbisamtb

typedef void __fastcall (__closure
      *TCustomFunctionEvent)(System::TObject* Sender, const
      System::UnicodeString FunctionName, TDBISAMParams*
      FunctionParams, System::Variant &Result)

This type is used for the TDBISAMEngine OnCustomFunction event. Please see the Customizing the Engine topic for more information.