FD Statement

The FD statement defines the contents and length of a field that will be used subsequently by a CREATE statement (or statements) to form output records. A defined field within the input logical record may be selected for use in the output records if it is referred to, by name, by a subsequent CREATE statement.

Figure 1 shows how the FD statement is used to specify a field in an input record to be used in output records. The left-hand side of the figure shows that a field in the input record beginning at byte 50 is selected for use in the output record. The right-hand side of the figure shows that the field is to be placed at byte 20 in the output record.

Figure 1. Field Selected from the Input Record for Use in the Output Record

When selecting fields from an input record (FD INPUT=ddname), the field must be defined by an FD statement within each set of utility control statements. In that case, defined fields for field selection are not usable across sets of utility control statements; such an FD record may be duplicated and used in more than one set of utility control statements within the job step.

You can also indicate that a numeric field is to be modified after it has been referred to n times by a CREATE statement or statements, that is, after n cycles, a modification is to be made. A modification will add a number you supply to a field.

The syntax of the FD statement is:

Label	Statement	Parameters
[label]	FD	NAME=name ,LENGTH=length [,STARTLOC=starting-location] [,FILL={'character\|X'nn'}] [,{FORMAT=pattern[,CHARACTER= character]\| PICTURE=length,{' character-string'\|P 'n'\|B }}] [,SIGN=sign] [,ACTION={ FX\|RO\|RP\|SL\|SR\|TL\|TR\|WV} [,INDEX=n [,CYCLE n][,RANGE= n]] [,INPUT=ddname] [,FROMLOC=number]

where:

NAME=name

specifies the name of the field defined by this FD statement.

LENGTH=length

specifies the length, in bytes, of the defined field. For variable records, the sum of the field must be four less than the maximum record length. This is to account for the four-byte record descriptor word.

If the INPUT parameter is specified, the LENGTH parameter overrides the length of each input logical record. If the combination of FROMLOC and LENGTH values is longer than the input record, the result is unpredictable.

For ACTION=RP or WV, the length is limited to 16383 bytes. For ACTION=RO, the length is limited to 10922 bytes.

STARTLOC=starting-location

specifies a starting location (within all output records using this field) in which a field is to begin. For example, if the first byte of an output record is chosen as the starting location, the keyword is coded STARTLOC=1; if the tenth byte is chosen, STARTLOC=10 is coded.

Default: The field will begin in the first available byte of the output record (determined by the order of specified field names in the applicable CREATE statement). For variable records, the starting location is the first byte after the length descriptor.

FILL={'character'|X 'nn'}

specifies a value that is to be placed in each byte of the field in the output record before any other operation in the construction of the field. These values can be coded:

'character': specifies a character that is to be converted to EBCDIC and placed in each byte of the output field.
X'nn': specifies 2 hexadecimal digits (for example, FILL=X'40', or FILL=X'FF') to be placed in each byte of the output field.

Default: Binary zeros are placed in the output field.

FORMAT=pattern[,CHARACTER=character]

specifies an IBM-supplied pattern that is to be placed in the defined field. FORMAT must not be used when PICTURE is used. The values that can be coded are:

pattern

specifies the IBM-supplied patterns, as follows:

AL: specifies an alphabetic pattern.
AN: specifies an alphanumeric pattern.
BI: specifies a binary pattern.
CO: specifies a collating sequence pattern.
PD: specifies a packed decimal pattern.
RA: specifies a random binary pattern.
ZD: specifies a zoned decimal pattern.

CHARACTER=character

specifies the starting character of a field.

PICTURE=length,{ 'character-string'|P'n'|B'n'}

specifies the length and the contents of a user-supplied pattern. PICTURE must not be used when FORMAT is used. If both PICTURE and NAME are omitted, the fill character specified in the CREATE statement appears in each byte of applicable output records. These values can be coded:

length: specifies the number of bytes that the pattern will occupy. Length must be equal to or less than the LENGTH parameter value in the FD statement.
'character-string': specifies a character string that is to be converted to EBCDIC and placed in the applicable records. The character string is left-aligned at the defined starting position. A character string may be broken in column 71, if you place a nonblank character in column 72 and continue the string in column 4 of the next statement. The number of characters within the quotation marks must equal the number specified in the length subparameter.
P'n': specifies a decimal number that is to be converted to packed decimal and right-aligned (within the boundaries of the defined length and starting byte) in the output records or defined field. The number of characters within the quotation marks must equal the number specified in the length subparameter.
B'n': specifies a decimal number that is to be converted to binary and right-aligned (within the boundaries of the defined length and starting byte) in the output records or defined field. The number of characters within the quotation marks must equal the number specified in the length subparameter.

SIGN=sign

specifies a mathematical sign (+ or -), to be used when defining a packed decimal or binary field.

Default: Positive (+).

ACTION={FX|RO|RP|SL|SR|TL|TR|WV}

specifies how the contents of a defined field are to be altered (if at all) after the field's inclusion in an output record.

. These values can be coded:

FX: specifies that the contents of a defined field are to remain fixed after the field's inclusion in an output record.
FX is the default.
RO: specifies that the contents of a defined field are to be rolled after the field's inclusion in an output record. The pattern ("picture") is moved to the left by one byte for each output record, until the first nonblank character of the picture is in the first byte of the field. Then, the picture is moved to the right one byte for each output record, until it returns to its original position in the field.
RO can be used only for a user-defined pattern. For RO to be effective, the picture length must be less than the field length.
RP: specifies that the contents of a defined field are to be rippled after the field's inclusion in an output record.
SL: specifies that the contents of a defined field are to be shifted left after the field's inclusion in an output record.
SR: specifies that the contents of a defined field are to be shifted right after the field's inclusion in an output record.
TL: specifies that the contents of a defined field are to be truncated left after the field's inclusion in an output record.
TR: specifies that the contents of a defined field are to be truncated right after the field's inclusion in an output record.
WV: specifies that the contents of a defined field are to be waved after the field's inclusion in an output record. The pattern ("picture") is moved to the left by one byte for each output record, until the first nonblank character of the picture is in the first byte of the field. Then the character string is reset to its original position.
WV can be used only for a user-defined pattern. For WV to be effective, the picture length must be less than the field length.

INDEX=n[,CYCLE=n] [,RANGE=n]

specifies a decimal number to be added to this field whenever a specified number of records have been written. INDEX is valid only with FORMAT patterns ZD, PD and BI, or PICTURE patterns P'n' and n . Additional values can be coded:

CYCLE=n: specifies a number of output records (to be written as output or made available to an exit routine) that are treated as a group by the INDEX keyword. Whenever this field has been used in the construction of the specified number of records, it is modified as specified in the INDEX parameter. For example, if CYCLE=3 is coded, output records may appear as 111 222 333 444, and so forth. This parameter can be coded only when INDEX is coded.
RANGE=n: specifies an absolute value which the contents of this field can never exceed. If an index operation tries to exceed the specified absolute value, the contents of the field as of the previous index operation are used.

Default: No indexing is performed. If CYCLE is omitted and INDEX is coded, a CYCLE value of 1 is assumed; that is, the field is indexed after each inclusion in a potential output record.

INPUT=ddname

specifies the ddname of a DD statement defining a data set used as input for field selection. Only a portion of the record described by the FD statement will be placed in the output record. If the record format of the output data set indicates variable-length records, the position within the output record will depend upon where the last insertion into the output record was made unless STARTLOC is specified.

The ddname SYSIN must not be coded in the INPUT parameter on the FD control statement. Each ddname should not appear more than once on any control statement.

A corresponding ddname must also be specified in the associated CREATE statement in order to have the input records read.

FROMLOC=number

specifies the location of the selected field within the input logical record. The number represents the position in the input record. If, for example, FROMLOC=10 is coded, the specified field begins at the tenth byte; if FROMLOC=1 is coded, the specified field begins at the first byte. (For variable-length records, significant data begins in the first byte after the 4-byte length descriptor.)

When retrieving data sets with fixed or fixed-blocked record formats and RKP>0, the record consists of the key plus the data with embedded key. To copy the entire record, the output logical record length has to be the input logical record length plus the key length. If only the data (which includes the embedded key) is to be copied, set FROMLOC equal to the keylength.

Default: The start of the input record.

Related reading:

For information about starting characters, see IBM-Supplied Patterns .
For information about system actions compatible with FORMAT and PICTURE values, see Table 1.
For examples of IEBDG ACTION patterns, see Figure 1.