Compaq AAQ2G1FTK 16.4 Using Alignment Directives, Qualiers, and Flags

Managing Memory and Data Access
16.4 Using Alignment Directives, Qualifiers, and Flags
16.4 Using Alignment Directives, Qualifiers, and Flags
Alignment directives offer flexibility and selectivity: they alter the current
alignment by specifying new alignment information from within the source
program.
The forms of the alignment directives are as follows:
*DC SET ALIGNMENT
*DC SET NOALIGNMENT
*DC END-SET ALIGNMENT
*DC SET PADALIGN
*DC SET NOPADALIGN
*DC END-SET PADALIGN
The *DC SET ALIGNMENT directive and the *DC SET PADALIGN directive
function independently of each other, except when their scopes overlap in
the program source. In case of overlapping scope, the effect of the *DC SET
PADALIGN directive prevails.
The *DC SET ALIGNMENT directive specifies natural Alpha alignment of
elementary data items. The *DC SET PADALIGN specifies Alpha natural
alignment and padding.
The *DC SET NOALIGNMENT directive specifies OpenVMS VAX compatible
alignment.
The optional *DC END-SET ALIGNMENT directive terminates the current *DC
SET ALIGNMENT or *DC SET NOALIGNMENT directive that is currently in
effect.
The alignment of binary data that has been specified with the SYNCHRONIZED
clause is unaffected by the *DC SET ALIGNMENT and *DC SET PADALIGN
directives.
When you use an alignment directive or qualifier to align data in records, you
should consider whether the data will be written to a file to be accessed by
applications written in Compaq COBOL for OpenVMS VAX.
Note
These directives are not allowed in the PROCEDURE DIVISION of a
program source.
16.4.1 Order of Alignment Operations
Table 16–2 shows the order of precedence of the primary alignment qualifiers and
directives in Compaq COBOL.
16–6Managing Memory and Data Access