Data Division (cont.) [ COBOL/HP-UX Language Reference for the Series 700 and 800 ] MPE/iX 5.0 Documentation
COBOL/HP-UX Language Reference for the Series 700 and 800
Data Division (cont.)
The REDEFINES Clause
Function
The REDEFINES clause allows the same computer storage area to be
described by different data description entries.
General Format
Click here to view figure.
Note that level-number and data-name-1 or FILLER (ANS85) are shown in the
above format to improve clarity. Level-number, and data-name-1 and
FILLER (ANS85) are not part of the REDEFINES clause.
Syntax Rules
1. The REDEFINES clause, when specified, must immediately follow
data-name-1 or FILLER, (ANS85) or it can follow the PICTURE or
USAGE clause. (OSVS) (MF)
2. The level-numbers of data-name-1 and data-name-2 must be identical
but must not be 66 , 78 (MF) or 88.
3. This clause must not be used in level 01 entries in the File
Section, since multiple level 01 entries subordinate to an FD or
SD indicator represent implicit redefinitions of the same areas.
(See General Rule 2 of the section "The DATA RECORDS Clause"
in Chapter 5 , File Input and Output.)
________________________________________________________________________
|(MF) |
|This clause can be used on level 01 entries in the File Section. |
________________________________________________________________________
4. This clause must not be used in level 01 entries in the
Communication Section since multiple level 01 entries subordinate
to a CD indicator represent implicit redefinition of the same
area.
5. The data description for data-name-2 can contain a REDEFINES
clause and (OSVS) (VSC2) data-name-2 can be subordinate to an
entry which contains a REDEFINES clause. Its data description
cannot contain an OCCURS clause. However, data-name-2 can be
subordinate to an item whose data description entry contains an
OCCURS clause. In this case, the reference to data-name-2 in the
REDEFINES clause can not be subscripted or indexed. Neither the
original definition nor the redefinition can include an item whose
size is variable as defined in the OCCURS clause. (See the
section "The OCCURS Clause" in this chapter.)
________________________________________________________________________
|(MF) |
|The data description for data-name-2 can contain an OCCURS clause. |
________________________________________________________________________
6. No entry having a level-number numerically lower than the
level-number of data-name-2 and data-name-1 can occur between the
data description entries of data-name-2 and data-name-1.
________________________________________________________________________
|(OSVS) (VSC2) (MF) |
| |
| |
| |
|7. An external or internal floating-point data item can be the |
| subject or object of a REDEFINES clause. |
| |
________________________________________________________________________
General Rules
1. Redefinition starts at data-name-2 and ends when a level-number
less than or equal to that of data-name-2 is encountered.
2. When the level-number of data-name-1 is other than 01, it must
specify the same number of character positions that the data item
referenced by data-name-2 contains
________________________________________________________________________
|(OSVS) (ANS85) |
|except that the data-name-1 area can be either smaller than the |
|data-name-2 area |
________________________________________________________________________
________________________________________________________________________
|(MF) |
|or be larger than the data- name-2 area. In this case, extra storage |
|is reserved to provide sufficient storage for the number of |
|character positions in the largest of the redefining or redefined |
|items. |
________________________________________________________________________
It is important to observe that the REDEFINES clause specifies the
redefinition of a storage area, not of the data items occupying
the area.
3. Multiple redefinitions of the same character positions are
permitted. The entries giving the new descriptions of the
character positions must follow the entries defining the area
being redefined, without intervening entries that define new
character positions. Multiple redefinitions of the same character
positions must all use the data-name of the entry that originally
defined the area
________________________________________________________________________
|(VSC2) (OSVS) |
|or the data-name of any other preceding redefinition of that |
|entry. |
________________________________________________________________________
4. The entries giving the new description of the character positions
must not contain any VALUE clauses except in condition-name
entries.
5. Multiple level 01 entries subordinate to any given level indicator
(FD, CD or SD) represent implicit redefinitions of the same area.
________________________________________________________________________
|(ANS85) |
| |
| |
| |
|6. Data-name-2 must not be qualified even if it is not unique since |
| no ambiguity of reference exists in this case because of the |
| required placement of the REDEFINES clause within the source |
| program. |
| |
________________________________________________________________________
The RENAMES Clause
Function
The RENAMES clause permits alternative, possibly overlapping, groupings
of elementary items.
General Format
Click here to view figure.
Note that level-number 66 and data-name-1 are shown in the above format
to improve clarity. Level-number and data-name-1 are not part of the
RENAMES clause.
Syntax Rules
1. Any number of RENAMES entries can be written for a logical record.
2. All RENAMES entries referring to data items within a given logical
record must immediately follow the last data description entry of
the associated record description entry.
3. Data-name-2 and data-name-3 must be names of elementary items or
groups of elementary items in the same logical record, and cannot
be the same data-name. A 66 level entry cannot rename another 66
level entry nor can it rename a 77, 78, (MF) 88, or 01 entry.
4. Data-name-1 cannot be used as a qualifier, and can only be
qualified by the names of the associated level 01, FD, CD or SD
entries. Neither data-name-2 nor data-name-3 can have an OCCURS
clause in its data description entry nor be subordinate to an item
that has an OCCURS clause in its data description entry. (See the
section "The OCCURS Clause" .)
5. The beginning of the area described by data-name-3 must not be to
the left of the beginning of the area described by data-name-2.
The end of the area described by data-name-3 must be the right of
the end of the area described by data-name-2. Data-name-3,
therefore, cannot be subordinate to data-name-2.
6. Data-name-2 and data-name-3 can be qualified.
7. The words THRU and THROUGH are equivalent.
8. None of the items within the range, including data-name-2 and
data-name-3, if specified, can be an item whose size is variable
as defined in the section "The OCCURS Clause" in this chapter.
General Rules
1. When data-name-3 is specified, data-name-1 is a group item which
includes all elementary items starting with data-name-2 (if
data-name-2 is an elementary item) or the first elementary item in
data-name-2 (if data-name-2 is a group item), and concluding with
data-name-3 (if data-name-3 is an elementary item) or the last
elementary item in data-name-3 (if data-name-3 is a group item).
2. When data-name-3 is not specified, all of the attributes of
data-name-2 become the data attributes for data-name-1.
________________________________________________________________________
|(OSVS) (VSC2) |
| |
| |
| |
|3. When data-name-2 and data-name-3 are not explicitly qualified and|
| when no ambiguity of reference exists, implied qualification of |
| the 01 level item is used. |
| |
________________________________________________________________________
The SIGN Clause
Function
The SIGN clause specifies the position and the mode of representation of
the operational sign when it is necessary to describe these properties
explicitly.
General Format
Click here to view figure.
Syntax Rules
1. The SIGN clause can be specified only for a numeric data
description entry whose PICTURE contains the character "S" , or a
group item containing at least one such numeric data description
entry.
2. The numeric data description entries to which the SIGN clause
applies must be described, implicitly or explicitly, as USAGE IS
DISPLAY.
3. At most one SIGN clause can apply to any given numeric data
description entry.
________________________________________________________________________
|This rule is removed. (ANS85) |
________________________________________________________________________
4. If the CODE-SET clause is specified, any signed numeric data
description entries associated with that file description entry
must be described with the SIGN IS SEPARATE clause.
________________________________________________________________________
|(MF) |
|This restriction is not enforced. See the section "The CODE-SET |
|Clause" in the chapter File Input and Output. |
________________________________________________________________________
General Rules
1. The optional SIGN clause, if present, specifies the position and
the mode of representation of the operational sign for the numeric
data description entry to which it applies, or for each numeric
data description entry subordinate to the group to which it
applies. The SIGN clause applies only to numeric data description
entries whose PICTURE contains the character "S"; the "S"
indicates the presence of, but neither the representation nor,
necessarily, the position of the operational sign.
2. A numeric data description entry whose PICTURE contains the
character "S", but to which no optional SIGN clause applies, has
an operational sign, but neither the representation nor,
necessarily, the position of the operational sign is specified by
the character "S". In this (default) case, General Rules 3
through 5 do not apply to such signed numeric data items. The
representation of the default operational sign is defined in the
section "Selection of Character Representation and Radix" in
the chapter COBOL Concepts.
3. If the optional SEPARATE CHARACTER phrase is not present, then:
a. The operational sign will be presumed to be associated with
the leading (or, respectively, trailing) digit position of
the elementary numeric data item in a manner defined in the
section "Selection of Character Representation and Radix"
in the chapter COBOL Concepts.
b. The letter "S" in a PICTURE character-string is not counted
in determining the size of the item (in terms of standard
data format characters).
4. If the optional SEPARATE CHARACTER phrase is present, then:
a. The operational sign will be presumed to be the leading
(or, respectively, trailing) character position of the
elementary numeric data item; this character position is
not a digit position.
b. The letter "S" in a PICTURE character-string is counted in
determining the size of the item (in terms of standard data
format characters).
c. The operational signs for positive and negative are the
standard data format characters "+" and "-", respectively.
5. Every numeric data description entry whose PICTURE contains the
character "S" is a signed numeric data description entry. If a
SIGN clause applies to such an entry and conversion is necessary
for purposes of computation or comparisons, conversion takes place
automatically.
________________________________________________________________________
|(ANS85) |
| |
| |
| |
|6. If a SIGN clause is specified for an item (either an elementary |
| numeric data description entry or a group item) which is |
| subordinate to a group item for which a SIGN clause is also |
| specified, then the SIGN clause specified in the subordinate item|
| takes precedence. |
| |
________________________________________________________________________
________________________________________________________________________
|(OSVS) (VSC2) (MF) |
| |
| |
| |
|7. The SIGN clause is treated as documentary for external |
| floating-point items. For internal floating-point items, the |
| SIGN clause is invalid and will result in a diagnostic |
| message. |
| |
________________________________________________________________________
The SYNCHRONIZED Clause
Function
The SYNCHRONIZED clause specifies the alignment of an elementary item on
the natural boundaries of the computer memory.
________________________________________________________________________
|(XOPEN) |
|Although it is a part of the standard COBOL definition, this |
|feature is explicitly excluded from the X/Open COBOL language |
|definitions and should not be used in a conforming X/Open COBOL source|
|program. |
________________________________________________________________________
General Format
Click here to view figure.
Syntax Rules
1. This clause should only appear with an elementary item.
2. SYNC is an abbreviation for SYNCHRONIZED.
________________________________________________________________________
|(OSVS) (VSC2) |
| |
| |
| |
|3. The SYNCHRONIZED clause can appear with a non-elementary |
| item. |
| |
________________________________________________________________________
General Rules
1. SYNCHRONIZED RIGHT specifies that the elementary item is to be
positioned such that it will terminate on the right character
position of the natural boundary in which the elementary item is
placed.
________________________________________________________________________
|(MF) |
|It takes effect only if the IBMCOMP directive is set. |
________________________________________________________________________
2. Specification of the LEFT phrase in the SYNCHRONIZED clause will
have no effect.
3. The effect of the SYNCHRONIZED clause is, by definition,
implementation- dependent. See your COBOL System Reference for
details.
4. This clause specifies that the subject data item is to be aligned
in the computer such that no other data item occupies any of the
character positions between the leftmost and rightmost natural
boundaries of the computer memory which delimits this data item.
If the number of character positions required to store this data
item is less than the number of character positions between those
natural boundaries, the unused character positions (or portions
thereof) must not be used for any other data item. Such unused
character positions, however, are included in:
a. The size of any group item(s) to which the elementary item
belongs, and:
b. The character positions redefined when this data item is
the object of a REDEFINES clause.
Thus the size of an elementary item is unchanged by the
SYNCHRONIZED clause, but extra character positions are assigned by
the use of the clause.
5. SYNCHRONIZED not followed by either RIGHT or LEFT specifies that
the elementary item is to be positioned between natural boundaries
in such a way as to use the elementary data item efficiently.
6. Whenever a SYNCHRONIZED item is referenced in the source program,
the original size of the item, as shown in the PICTURE clause, is
used in determining any action that depends on size, such as
justification, truncation or overflow.
7. If the data description of an item contains the SYNCHRONIZED
clause and an operational sign, the sign of the item appears in
the normal operational sign position, regardless of whether the
item is SYNCHRONIZED LEFT or SYNCHRONIZED RIGHT.
8. When the SYNCHRONIZED clause is specified in a data description
entry of a data item that also contains an OCCURS clause, or in a
data description entry of a data item subordinate to a data
description entry that contains an OCCURS clause, then:
a. Each occurrence of the data item is SYNCHRONIZED.
b. Any implicit FILLER generated for other data items within
that same table are generated for each occurrence of those
data items.
________________________________________________________________________
|(OSVS) (VSC2) |
| |
| |
| |
|9. If the SYNCHRONIZED clause is specified with a non-elementary |
| item, then the clause applies to all the items subordinate to |
| that non-elementary item. |
| |
________________________________________________________________________
10. The effect of the use of the SYNCHRONIZED clause is discussed in the
section "Selection of Character Representation and Radix" in the
chapter COBOL Concepts.
The USAGE Clause
Function
The USAGE clause specifies the format of a data item in the computer
storage.
General Format
Click here to view figure.
Syntax Rules
1. The PICTURE character-string of a COMPUTATIONAL,
COMPUTATIONAL-3, (OSVS) (VSC2) (MF) (XOPEN)
or COMPUTATIONAL-5 (MF) (XOPEN)
BINARY, PACKED-DECIMAL (ANS85) item can contain only "9"s, the
operational sign character "S", the implied decimal point
character "V" , one or more "P"s. (See the section "The PICTURE
Clause" earlier in this chapter.)
2. COMP is an abbreviation for COMPUTATIONAL.
________________________________________________________________________
|(ANS85) |
| |
| |
| |
|3. BINARY is equivalent to COMPUTATIONAL. |
| |
________________________________________________________________________
________________________________________________________________________
|(OSVS) (VSC2) (MF) |
| |
| |
| |
|4. COMP-4 is an abbreviation for COMPUTATIONAL-4 and is equivalent |
| to COMPUTATIONAL. |
| |
________________________________________________________________________
________________________________________________________________________
|(MF) (OSVS) (VSC2) (XOPEN) |
| |
| |
| |
|5. COMP-3 is an abbreviation for COMPUTATIONAL-3. |
| |
________________________________________________________________________
________________________________________________________________________
|(ANS85) |
| |
| |
| |
|6. PACKED-DECIMAL is equivalent to COMPUTATIONAL-3. |
| |
________________________________________________________________________
________________________________________________________________________
|(MF) (XOPEN) |
| |
| |
| |
|7. COMP-5 is an abbreviation for COMPUTATIONAL-5. |
| |
________________________________________________________________________
________________________________________________________________________
|(OSVS) (VSC2) (MF) |
| |
| |
| |
|8. COMP-1 is an abbreviation for COMPUTATIONAL-1. |
| |
|9. COMP-2 is an abbreviation for COMPUTATIONAL-2. |
| |
________________________________________________________________________
10. The USAGE clause cannot be specified for level 66 or 88 data
description entries.
________________________________________________________________________
|(MF) |
| |
| |
| |
|11. The PICTURE character-string of a COMPUTATIONAL-X item must |
| consist either of all "9" s or of all "X"s. Either gives an item|
| whose category is numeric. |
| |
|12. The PICTURE clause of an elementary item can contradict the USAGE|
| clause of a group to which the item belongs. In this case the |
| USAGE specified at the group level will be ignored for that |
| elementary item. |
| |
________________________________________________________________________
________________________________________________________________________
|(VSC2) (MF) |
| |
| |
| |
|13. The SYNCHRONIZED, JUSTIFIED, PICTURE, VALUE, SIGN and BLANK WHEN |
| ZERO clauses cannot be used to describe group or elementary items|
| described with the USAGE IS POINTER clause. |
| |
________________________________________________________________________
14. An index data item can be referenced explicitly only in a SEARCH or
SET statement, a relation condition, the USING phrase of a Procedure
Division header, the USING phrase of an ENTRY statement (OSVS)
(VSC2) (MF) or the USING phrase of a CALL statement.
15. The SYNCHRONIZED, JUSTIFIED, PICTURE, VALUE, SIGN and BLANK WHEN
ZERO clauses cannot be used to describe group or elementary items
described with the USAGE IS INDEX clause.
________________________________________________________________________
|(OSVS) (VSC2) |
|The SYNCHRONIZED clause can be used to describe group or elementary |
|items described with the USAGE IS INDEX clause. |
________________________________________________________________________
16. An elementary data item described with a USAGE IS INDEX clause can
not be a conditional variable.
________________________________________________________________________
|(OSVS) (VSC2) (MF) |
| |
| |
| |
|17. COMPUTATIONAL-1 and COMPUTATIONAL-2 items (internal |
| floating-point) cannot have PICTURE strings. |
| |
________________________________________________________________________
________________________________________________________________________
|(MF) |
| |
| |
| |
|18. A declaration with USAGE IS PROCEDURE-POINTER must contain no |
| other data description clauses. |
| |
________________________________________________________________________
General Rules
1. The USAGE clause can be written at any level. If the USAGE clause
is written at group level, it applies to each elementary item in
the group but does not have any effect on the allowed use of the
group item. The USAGE clause of an elementary item cannot
contradict the USAGE clause of a group to which the item belongs.
2. The USAGE clause specifies the manner in which an elementary data
item is represented in the storage of a computer. It does not
affect the use of the data item, although the specifications for
some statements in the Procedure Division can restrict the
operands to elementary items with particular USAGE clauses. The
USAGE clause can affect the radix or type of character
representation of the item.
3. A COMPUTATIONAL, COMPUTATIONAL-3, (OSVS) (VSC2) (MF)
(XOPEN) COMPUTATIONAL-5, (MF) (XOPEN) COMPUTATIONAL-X,(MF)
PACKED-DECIMAL,or BINARY (ANS85) item is capable of representing
a value to be used in computations and must be numeric. If a
group item is described with one of these clauses, the clause
applies to the elementary items in the group, not to the group
item itself; the group item cannot be used in computations. The
effect of these clauses is discussed in the section "Selection of
Character Representation and Radix" in the chapter COBOL
Concepts.
4. The USAGE IS DISPLAY clause indicates that the format of the data
is a standard data format.
5. If the USAGE clause is not specified for an elementary item, or
for any group to which the item belongs, the usage is implicitly
DISPLAY.
________________________________________________________________________
|(OSVS) (VSC2) (MF) |
| |
| |
| |
|6. The USAGE IS DISPLAY clause is valid for the following types of |
| items: |
| |
| |
| * Alphabetic |
| |
| * Alphanumeric |
| |
| * Alphanumeric-edited |
| |
| * Numeric-edited |
| |
| * External floating-point |
| |
| * External decimal (numeric) |
| |
________________________________________________________________________
7. Space requirements and storage definitions for the various USAGE
storage options are given under the section "Selection of Character
Representation and Radix" in the chapter COBOL concepts.
________________________________________________________________________
|(MF) (VSC2) |
| |
| |
| |
|8. The USAGE IS POINTER clause identifies a data item in which you |
| can store the address of a data item (see the section "The SET |
| Statement" in this chapter). |
| |
________________________________________________________________________
________________________________________________________________________
|(MF) |
| |
| |
| |
|9. The USAGE IS PROCEDURE-POINTER clause specifies that a data item |
| is a procedure pointer data item in which you can store the |
| address of a procedure. (See "The SET Statement" in this |
| chapter.) The procedure can be written in any language: if |
| COBOL, it represents the Procedure Division of a program that is |
| not nested and identified by either: |
| |
| the program-name of the PROGRAM-ID paragraph; or |
| |
| the entry-name of an ENTRY statement. |
| |
________________________________________________________________________
10. An elementary item described with the USAGE IS INDEX clause is
called an index data item and contains a value which must correspond
to an occurrence number of a table element. The elementary item
cannot be a conditional variable. Your COBOL system will allocate a
4-byte binary field with an implied PICTURE of 9(9) COMP. If a group
item is described with the USAGE IS INDEX clause the elementary
items in the group are all index data items. The group itself is
not an index data item and cannot be used in a SEARCH or SET
statement or in a relation condition.
11. An index data item , pointer data item or procedure pointer data
(MF) item can be part of a group which is referred to in a MOVE or
input-output statement, in which case no conversion will take place.
Your COBOL system will allocate a 4-byte binary field for the data
item.
MPE/iX 5.0 Documentation
HP 3000 Manuals