TRUNCATE

 The TRUNCATE attribute indicates that an actual  parameter  list
 for  a  routine can be truncated at the point that the attribute
 was specified.

 This attribute can be specified  on  a  formal  parameter  in  a
 routine declaration, and can be used with the PRESENT function.

 See the "HP Pascal Language Reference Manual" for  the  complete
 description of using the TRUNCATE attribute.