5.3.16.6 "COBOL Language Reference" IBM Library Server

X 5.3.16.6 POINTER Phrase

X A data item defined with USAGE IS POINTER is a pointer data item. A
X pointer data item is a 4-byte elementary item,

X You can use pointer data items to accomplish limited base addressing.
X Pointer data items can be compared for equality or moved to other pointer
X items.

X A pointer data item can only be used:

X In a SET statement (Format 5 only)
X In a relation condition
X In the USING phrase of a CALL statement, an ENTRY statement, or the
X Procedure Division header.

X The USAGE IS POINTER clause can be written at any level except level 88.
X If a group item is described with the USAGE IS POINTER clause, the
X elementary items within the group are pointer data items; the group itself
X is not a pointer data item and cannot be used in the syntax where a
X pointer data item is allowed. The USAGE clause of an elementary item
X cannot contradict the USAGE clause of a group to which the item belongs.

X Pointer data items can be part of a group that is referred to in a MOVE
X statement or an input/output statement. However, if a pointer data item
X is part of a group, there is no conversion of values when the statement is
X executed.

X A pointer data item can be the subject or object of a REDEFINES clause.

X SYNCHRONIZED can be used with USAGE IS POINTER to obtain efficient use of
X the pointer data item.

X A VALUE clause for a pointer data item can contain only NULL or NULLS.

X A pointer data item cannot be a conditional variable.

X A pointer data item does not belong to any class or category.

X The DATE FORMAT, JUSTIFIED, PICTURE, and BLANK WHEN ZERO clauses cannot be
X used to describe group or elementary items defined with the USAGE IS
X POINTER clause.

X Pointer data items are ignored in CORRESPONDING operations.

X A pointer data item can be written to a data set, but, upon subsequent
X reading of the record containing the pointer, the address contained can no
X longer represent a valid pointer.

X Note: USAGE IS POINTER is implicitly specified for the ADDRESS OF special
X register. For more information see the IBM COBOL Programming Guide for
X your platform.

Adobe, the Adobe logo, Acrobat, the Acrobat logo, and Acrobat Reader are registered trademarks of Adobe Systems incorporated.

X 5.3.16.6 POINTER Phrase

IBM Library Server Copyright 1989, 2005 IBM Corporation. All rights reserved.