Compiler Error C0239

Message: Interface <interface name 1> does not extend <interface name 2>

Possible error cause: The used interface does not extend another interface.

Error correction: Extend the interface.

Example 457. Example of the error:

PROGRAM PLC_PRG
VAR
    ITFref : ITF;
    ITFref2 : ITF2;
END_VAR

__QueryInterface(ITFref2,ITFref);

INTERFACE ITF
INTERFACE ITF2 EXTENDS ITF

Message:

C0239: Interface ITF does not extend __System.IQueryInterface

Error correction:

INTERFACE ITF EXTENDS __System.IQueryInterface