DCLDSFLD

Declares a subfield for a data structure.

DCLDSFLD
Name  (name)
Type (*BINARY | *BOOLEAN | *BYTE | *CHAR | *DATE | *DECIMAL | *FLOAT | *FLOAT4 |
      *FLOAT8 | *IND | *INTEGER | *INTEGER2 | *INTEGER4 | *INTEGER8 | *ONECHAR |
      *PACKED | *TIME | *TIMESTAMP | *ZONED)
Len (Integer Literal, Interger Literal)
Dim (Integer Literal, Integer Literal, ...)
TimFmt (*PGMDFT | *DMY | *EUR | *HMS | *ISO | *JIS | *JUL | *MDY | *USA | *YMD)
Like (Field name)
Overlay (parentField, startPos | *Next)
OverlayArray (parentField, startPos | *Next)

Parts

Name

Required. The name of the data structure subfield.

Type

Optional. Type can be any of Special Value ( i.e., *CHAR, *BINARY, etc.) or it can be a class name. If Type is *BOOLEAN or *IND, you can use *ON, *TRUE, *ON and *FALSE figurative constants to indicate true and false and "1" and "0", respectively.

If a Type parameter is not given, the Len parameter is required. In this case, *CHAR is assumed if there is one integer given and *ZONED is assumed if there are two integers.

Len

Optional. Len specifies the length of the field. If Len is decimal e.g. Len (3,1) *ZONED is assigned as the default. If Len is character e.g. Len (3), *CHAR is assigned as the default.

If Type is packed, then the length is not the number of bytes the packed field fits into, but rather the logical digit length of the field. For example, if you want a 7 digit packed with 2 decimals, code Len (7,2).

Dim

Optional. When Dim is specified, the DCLDSFLD is treated as an array with all the properties associated with a DCLARRAY statement.

TimFmt

Optional. TimFmt specifies the format for time, date, and timestamp variables. If the TimFmt parameter is not specified, the format specified by the program is assumed.

Like

Optional. Like must be the name of a field already defined in the class. Type cannot be a named constant or a literal. In this case, the field will be defined based on the attributes of another field. If Type is an array, array element, or a table name, the attributes of an element of the array or table are used to define the field. You can use Len parameter to make the declared field longer or shorter than the Like parameter entry.

A plus sign (+) preceding the number indicates a length increase; a minus sign (-) indicates a length decrease. You cannot change the number of decimal positions for the field being defined. The field length entry is allowed only for field definitions requiring a length.

Overlay

Optional. For Type *CHAR and *ZONED only. The OVERLAY keyword overlays the storage of one subfield with that of another subfield.

This subfield will overlay the storage specified by the overlaid name parameter at the position specified by the startpos parameter. If startpos is not specified, it defaults to 1.

parentField - The name of a subfield defined previously in the current data structure. See further information below.

startPos - Optional. Can be an integer, or *NEXT. Specifying Overlay (Name:*Next), positions the subfield at the next available position within the overlaid field. This will be the first byte past all other subfields prior to this subfield that overlays the same subfield. Note: The startpos parameter is in units of bytes, regardless of the types of the subfields. See further information below.

The following rules apply to keyword OVERLAY:

The overlaid name parameter must be the name of a subfield defined previously in the current data structure.
The startpos parameter (if specified) must be a value greater than 0 with no decimal positions. It can be a numeric literal, a built-in function returning a numeric value, or a numeric constant. If startpos is a named constant, it must be defined prior to this specification.
If the overlaid name parameter is a subfield, the subfield being defined must be contained completely within the subfield specified by the overlaid name parameter.
Alignment of subfields defined using the OVERLAY keyword must be done manually. If they are not correctly aligned, a warning message is issued.
If a subfield with overlaying subfields is not otherwise defined, the subfield is implicitly defined as follows:
If the subfield specified by overlaid name is an array, the OVERLAY keyword applies to each element of the array. See restrictions below.

That is, the field being defined is defined as an array with the same number of elements. The first element of this array overlays the first element of the overlaid array, the second element of this array overlays the second element of the overlaid array, and so on. No array keywords may be specified for the subfield with the OVERLAY keyword in this situation.

If the subfield specified by overlaid name is an array and its element length is longer than the length of the subfield being defined, the array elements of the subfield being defined are not stored contiguously.

Restrictions when the overlaid name is an array:

Under such a declaration, the subfield becomes a non-contiguous array and has the following usage limitations.

Not valid on Result Field of PARM.
Not valid on Factor2 or Result Field of MOVEA.
When used with a SORTA, the 'parent' array is sorted according to the data values of the non-contiguous array elements.
Allowed on an XFOOT.
When on the left side of an assignment and used with no index, it follows the rules of having an array on the left (i.e. runs a loop to assign to every element of the array.

OverlayArray

Optional. The OverlayArray keyword is used to define a field to overlay an array subfield. The elements of the array subfield will be concatenated into one large scalar field, before overlaying occurs ( RPG/400 behavior ).

This is in contrast to the Overlay keyword, which is an element-by-element overlay( RPG/ILE behavior ). Hence in-effect, using Overlay keyword to define an overlay field on an array subfield, the field will be defined as an Array; where as in OverlayArray, the field will be defined as a Scalar.

parentField - Must be an array.

startPos - Optional. Can be an integer, or *NEXT. Specifying OverlayArray (Name:*Next), positions the subfield at the next available position within the overlaid field. This will be the first byte past all other subfields prior to this subfield that overlays the same subfield.

Example

DCLDS Name(DS1)
DCLDSFLD Name(DSFLD1)    Type(*CHAR) Len(5)
DCLDSFLD Name(DSFLD2)    Type(*ZONED) Len(10,0)
DCLDSFLD Name(OVERDSFLD) Type(*CHAR) Len(10) Overlay(DSFLD2)

// Declare a simple data structure with two subfields with one overlay of the 1st five characters of DSFLD2
DCLDS Name(DS1)
DCLDSFLD Name(DSFLD1)    Type(*CHAR) Len(5)
DCLDSFLD Name(DSFLD2)    Type(*CHAR) Len(10)
DCLDSFLD Name(OVERDSFLD) Type(*CHAR) Len(5) Overlay(DSFLD2,1)

DCLDSFLD - Declare a Subfield for a Data Structure

Parts

Example

See Also