Use to test your assumptions about the validity of an object's internal state.
ASSERT_VALID calls the AssertValid member function of the object passed as its argument.
In the Release version of MFC, ASSERT_VALID does nothing. In the Debug version, it validates the pointer, checks against NULL, and calls the object's own AssertValid member functions. If any of these tests fails, an alert message is displayed in the same manner as ASSERT.
This function is available only in the Debug version of MFC.
For more information and examples, see Debugging MFC Applications.