The ALERT structure is used in the ALERT_VECTOR structure, which is used in the Alerts field of the ALERT_MESSAGE structure message, as specified in section 2.2.6.6. 

 struct
 {
   ULONG AlertType;
   BYTE_VECTOR AlertValue;
 } ALERT; 

AlertType: A ULONG that indicates the type of the alert.

AlertValue: A BYTE_VECTOR structure, as specified in section 2.2.5.2.3, that contains an array of alert values.