A Commodities Exchange function that acts on a CxObject records errors in the CxObject's accumulated error field. The function CxObjError() returns a CxObject's error field. co_errorfield = LONG CxObjError( CxObj *co ); Each bit in the error field corresponds to a specific type of error. The following is a list of the currently defined CxObject errors and their corresponding bit mask constants. COERR_ISNULL CxObjError() was passed a NULL. COERR_NULLATTACH Someone tried to attach a NULL CxObj to this CxObj. COERR_BADFILTER This CxObj is a filter and currently has an invalid filter description. COERR_BADTYPE Someone tried to perform a type specific function on the wrong kind of CxObject (for example calling SetFilter() on a sender CxObject). The remaining bits are reserved by Commodore for future use. HotKey checks the error field of its filter CxObject to make sure the filter is valid. HotKey does not need to check the other objects with CxObjError() because it already makes sure that thes e other objects are not NULL, which is the only other kind of error the other objects can cause in this situation.