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Accessing Tape Devices
*.. 1 ...+... 2 ...+... 3 ...+... 4 ...+... 5 ...+... 6 ...+... 7 ...+... *
FFilename++IPEASFRlen+LKlen+AIDevice+.Keywords+++++++++++++++++++++++++++++
FPRINT O F 132 PRINTER PRTCTL(LINE)
*.. 1 ...+... 2 ...+... 3 ...+... 4 ...+... 5 ...+... 6 ...+... 7 ...+... *
DName+++++++++++ETDsFrom+++To/L+++IDc.Keywords+++++++++++++++++++++++++++++
DLINE DS
D SpBefore 1 3
D SpAfter 4 6
D SkBefore 7 9
D SkAfter 10 12
D CurLine 13 15 0
*.. 1 ...+... 2 ...+... 3 ...+... 4 ...+... 5 ...+... 6 ...+... 7 ...+... *
CL0N01Factor1+++++++Opcode(E)+Factor2+++++++Result++++++++Len++D+HiLoEq....
C EXCEPT
C 01CurLine COMP 10 49
C 01
CAN 49 MOVE '3' SpAfter
*.. 1 ...+... 2 ...+... 3 ...+... 4 ...+... 5 ...+... 6 ...+... 7 ...+... *
OFilename++DF..N01N02N03Excnam++++B++A++Sb+Sa+.............................
OPRINT E 01
O..............N01N02N03Field+++++++++YB.End++PConstant/editword/DTformat++
O DATA 25
Figure 161. Example of the PRTCTL Option
On the file description specifications, the PRTCTL keyword is specified for the
PRINT file. The name of the associated data structure is LINE.
The LINE data structure is defined on the input specifications as having only those
subfields that are predefined for the PRTCTL data structure. The first four subfields
in positions 1 through 12 are used to supply space and skip information that is
generally specified in positions 40 through 51 of the output specifications. The
PRTCTL keyword allows you to change these specifications within the program.
In this example, the value in the SpAfter subfield is changed to 3 when the value in
the CurLine (current line count value) subfield is equal to 10. (Assume that indi-
cator 01 was set on as a record identifying indicator.)
Accessing Tape Devices
Use the SEQ device specifications whenever you write to a tape file. To write
variable-length records to a tape file, use the RCDBLKFMT parameter of the CL
command CRTTAPF or OVRTAPF. When you use the RCDBLKFMT parameter,
the length of each record to be written to tape is determined by:
the highest end position specified in the output specifications for the record or,
if you do not specify an end position, the compiler calculates the record length
from the length of the fields.
Read variable-length records from tape just like you would read records from any
sequentially organized file. Ensure the record length specified on the file description
specification accommodates the longest record in the file.
Chapter 17. Accessing Externally Attached Devices 325