pTAL Reference Manual (H06.08+)

Structures

HP pTAL Reference Manual—523746-006

9-33

VOLATILE Attribute

The VOLATILE attribute specifies that the value of this variable must be maintained in

memory, not in a register. Each reference to a VOLATILE data item causes the data

item to be read or written to memory even when code is optimized. Based on the order

of reads and writes in the source code, VOLATILE also causes that precise order of

memory references to be preserved, again, when code is optimized.

You can specify the VOLATILE attribute on any field except a substructure.

The syntax and semantics of VOLATILE fields and VOLATILE pointer fields is the

same as those of VOLATILE variables and pointers, respectively.

Declaring Definition Structures

.EXT

.SG

.SGX

are indirection symbols (see Table 2-7 on page 2-7).

identifier

is the identifier of the new referral structure.

Example 9-28. VOLATILE Attribute

STRUCT s;

BEGIN

VOLATILE INT a; ! A simple VOLATILE field

VOLATILE INT .EXT b; ! A VOLATILE extended pointer

VOLATILE INT .c REFALIGNED(2); ! A VOLATILE standard pointer

END; ! with a REFALIGNED clause

STRUCT

identifier

.EXT

.SG

.SGX

range field-alignment

structure-layout

;

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