TAL Programmer's Guide

Equivalencing Structure Pointers
Using Equivalenced Variables
10–16 096254 Tandem Computers Incorporated
Declaring Equivalenced
Structure Pointers
To declare an equivalenced structure pointer, specify:
STRING or INT attribute (as described in Table 9-3 in Section 9)
The identifier of the new structure pointer, preceded by an indirection symbol
A referral that provides a structure layout—enclose the identifier of a previously
declared structure or structure pointer in parentheses
An equal sign (=)
The identifier of the previous variable
For portability to future software platforms, declare equivalenced variables that fit
within the previous variable.
Equivalencing Structure Pointers to Structure Pointers
You can declare a structure pointer equivalent to another structure pointer as
follows:
STRUCT temp (*);
BEGIN
STRING s[0:71];
END;
STRUCT .EXT str;
BEGIN
STRING name[0:20];
STRING addr[0:50];
END;
INT .EXT ptr1 (str) := @str;
INT .EXT ptr2 (temp) = ptr1;
Primary area of user data segment
STR
320
Automatic extended data segment
PTR2
ptr to STR
PTR1
.
.
.