Rules for Control Level Indicators
Rules for Control Level Indicators
When you assign control level indicators, remember the following:
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You can specify control fields only for primary or secondary files.
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You cannot specify control fields for full procedural files; numeric input fields of type binary, integer, unsigned or float; or look-ahead fields.
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You cannot use control level indicators when an array name is specified in positions 49 through 62 of the input specifications; however, you can use control level indicators with an array element. Control level indicators are not allowed for null-capable fields.
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Control level compare operations are processed for records in the order in which they are found, regardless of the file from which they come.
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If you use the same control level indicator in different record types or in different files, the control fields associated with that control level indicator must be the same length (see Figure 1) except for date, time, and timestamp fields which need only match in type (that is, they can be different formats).
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The control level indicator field length is the length of a control level indicator in a record. For example, if L1 has a field length of 10 bytes in a record, the control level indicator field length for L1 is 10 positions.
The control level indicator field length for split control fields is the sum of the lengths of all fields associated with a control level indicator in a record. If L2 has a split control field consisting of 3 fields of length: 12 bytes, 2 bytes and 4 bytes; then the control level indicator field length for L2 is 18 positions.
If multiple records use the same control level indicator, then the control level indicator field length is the length of only one record, not the sum of all the lengths of the records.
Within a program, the sum of the control level indicator field lengths of all control level indicators cannot exceed 256 positions.
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Record positions in control fields assigned different control level indicators can overlap in the same record type (see Figure 2). For record types that require control or match fields, the total length of the control or match field must be less than or equal to 256. For example, in Figure 2, 15 positions have been assigned to control levels.
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Field names are ignored in control level operations. Therefore, fields from different record types that have been assigned the same control level indicator can have the same name.
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Control levels need not be written in any sequence. An L2 entry can appear before L1. All lower level indicators need not be assigned.
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If different record types in a file do not have the same number of control fields, unwanted control breaks can occur.
Figure 3 shows an example of how to avoid unwanted control breaks.
Figure 1. Control Level Indicators (Two Record Types)
*...1....+....2....+....3....+....4....+....5....+....6....+....7...
A* EMPLOYEE MASTER FILE -- EMPMSTL
A R EMPREC PFILE(EMPMSTL)
A EMPLNO 6
A DEPT 3
A DIVSON 1
A*
A* (ADDITIONAL FIELDS)
A*
A R EMPTIM PFILE(EMPMSTP)
A EMPLNO 6
A DEPT 3
A DIVSON 1
A*
A* (ADDITIONAL FIELDS)
*...1....+....2....+....3....+....4....+....5....+....6....+....7...
IFilename++SqNORiPos1+NCCPos2+NCCPos3+NCC................................
I........................Fmt+SPFrom+To+++DcField+++++++++L1M1FrPlMnZr....
*
* In this example, control level indicators are defined for three
* fields. The names of the control fields (DIVSON, DEPT, EMPLNO)
* give an indication of their relative importance.
* The division (DIVSON) is the most important group.
* It is given the highest control level indicator used (L3).
* The department (DEPT) ranks below the division;
* L2 is assigned to it. The employee field (EMPLNO) has
* the lowest control level indicator (L1) assigned to it.
*
IEMPREC 10
I EMPLNO L1
I DIVSON L3
I DEPT L2
*
* The same control level indicators can be used for different record
* types. However, the control fields having the same indicators must
* be the same length. For records in an externally described file,
* the field attributes are defined in the external description.
*
IEMPTIM 20
I EMPLNO L1
I DEPT L2
I DIVSON L3Figure 2. Overlapping Control Fields
Figure 3. How to Avoid Unwanted Control Breaks
*...1....+....2....+....3....+....4....+....5....+....6....+....7...
IFilename++SqNORiPos1+NCCPos2+NCCPos3+NCC................................
I........................Fmt+SPFrom+To+++DcField+++++++++L1M1FrPlMnZr....
ISALES 01
I 1 2 L2FLD L2
I 3 15 NAME
IITEM 02
I 1 2 L2FLD L2
I 3 5 L1FLD L1
I 6 8 AMT
CL0N01Factor1+++++++Opcode(E)+Factor2+++++++Result++++++++Len++D+HiLoEq..
* Indicator 11 is set on when the salesman record is read.
*
C 01 SETON 11
*
* Indicator 11 is set off when the item record is read.
* This allows the normal L1 control break to occur.
*
C 02 SETOFF 11
C 02AMT ADD L1TOT L1TOT 5 0
CL1 L1TOT ADD L2TOT L2TOT 5 0
CL2 L2TOT ADD LRTOT LRTOT 5 0
**...1....+....2....+....3....+....4....+....5....+....6....+....7...
OFilename++DF..N01N02N03Excnam++++B++A++Sb+Sa+...........................
O..............N01N02N03Field+++++++++YB.End++PConstant/editword/DTformat
OPRINTER D 01 1 1
O L2FLD 5
O NAME 25
O D 02 1
O L1FLD 15
O AMT Z 15
*
* When the next item record causes an L1 control break, no total
* output is printed if indicator 11 is on. Detail calculations
* are then processed for the item record.
*
OFilename++DF..N01N02N03Excnam++++B++A++Sb+Sa+...........................
O..............N01N02N03Field+++++++++YB.End++PConstant/editword/DTformat
O T L1N11 1
O L1TOT ZB 25
O 27 '*'
O T L2 1
O L2TOT ZB 25
O 28 '**'
O T LR 1
O LRTOT ZB 25Different record types normally contain the same number of control fields. However, some applications require a different number of control fields in some records.
The salesman records contain only the L2 control field. The item records contain both L1 and L2 control fields. With normal RPG IV coding, an unwanted control break is created by the first item record following the salesman record. This is recognized by an L1 control break immediately following the salesman record and results in an asterisk being printed on the line below the salesman record.
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Numeric control fields are compared in zoned decimal format. Packed numeric input fields lengths can be determined by the formula:
d = 2n - 1Where d = number of digits in the field and n = length of the input field. The number of digits in a packed numeric field is always odd; therefore, when a packed numeric field is compared with a zoned decimal numeric field, the zoned field must have an odd length.
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When numeric control fields with decimal positions are compared to determine whether a control break has occurred, they are always treated as if they had no decimal positions. For instance, 3.46 is considered equal to 346.
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If you specify a field as numeric, only the positive numeric value determines whether a control break has occurred; that is, a field is always considered to be positive. For example, -5 is considered equal to +5.
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Date and time fields are converted to *ISO format before being compared
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Graphic data is compared by hexadecimal value