A SEQUENCE directive is defined to allow a user to declare explicitly that variables or COMMON blocks are to be treated by the compiler as sequential. (COMMON blocks are by default nonsequential. Variables are nonsequential unless Definition 5 applies.) Some implementations may supply an optional compilation environment where the SEQUENCE directive is applied by default. For completeness in such an environment, HPF defines a NO SEQUENCE directive to allow a user to establish that the usual nonsequential default should apply to a scoping unit, or selected variables and COMMON blocks within the scoping unit.
XBNF
sequence-directive -to -rule
to to is SEQUENCE [ [ :: ] association-name-list ]
-to or NO SEQUENCE [ [ :: ] association-name-list ]