pTAL Reference Manual (H06.08+)

Structures
HP pTAL Reference Manual—523746-006
9-53
Declaring Redefinitions
Declaring Redefinitions
A redefinition declares a new identifier and sometimes a new description for a previous
item in the same structure.
The following rules apply to all redefinitions in structures:
•
The new item must be of the same length or shorter than the previous item.
•
The new item and the previous item must be at the same BEGIN-END level of a
structure.
Table 9-8. Addresses in Structure Pointers
Addressing
Mode
STRING or
INT Attribute Kind of Address
Standard STRING* 16-bit byte address of a substructure, STRING simple
variable, or STRING array declared in a structure
Standard INT** 16-bit word address of any structure data item
Extended STRING* 32-bit byte address of any structure item located in any
segment, normally the automatic extended data segment
Extended INT** 32-bit byte address of any structure item located in any
segment, normally the automatic extended data segment
* If the pointer is the source in a move statement or group comparison expression that omits a count-unit,
the
count-unit is BYTES.
** If the pointer is the
source in a move statement or group comparison expression that omits a count-unit,
the
count-unit is WORDS.
Example 9-42. Declaring a Structure Pointer Within a Structure
STRUCT struct_a;
BEGIN
INT a;
INT b;
END;
STRUCT struct_b;
BEGIN
INT .EXT struct_pointer (struct_a);
STRING a;
END;