Reading Spool Files in RPG
October 18, 2002 Timothy Prickett Morgan
I have a problem similar to the one you solved in the February 27, 2002, issue of Midrange Guru. I wish to copy a spooled file that has been produced by a package, run an RPG program to modify the output, and build a new spooled file. In that example, you specified CTLCHAR(*FCFC) in the Copy Spooled File (CPYSPLF) command in order to use first-character form control characters. Can an RPG program interpret those characters and generate a new spool file with the same spacing?
If you only want to modify the lines and reprint them, consider updating the disk file and using the Copy File (CPYF) command with CTLCHAR(*FCFC), as in the technique to which you referred.
However, if you want to take more liberties with the new report, making an RPG program generate a fresh report is a good idea. It’s not difficult to make the RPG program read the first-character forms control characters and skip or space accordingly when it writes to a printer file. However, there’s an easier method that I have used several times.
Rather than CTLCHAR(*FCFC), use CTLCHAR(*PRTCTL). Doing so puts a four-byte prefix on each record of the disk file. The first three bytes contain either blanks or a skip-before entry. The fourth byte contains either a blank or a space-before entry.
In the following example, the printer skips to line 5 before printing the first line. It double-spaces before printing the second line and single-spaces before printing the third line:
005 12/25/2002 My Report Page 1 2Blah blah blah 1More blah blah blah
In the RPG program, use the PRTCTL keyword on the printer file’s F spec. This lets you use a data structure, rather than hard-coded skipping and spacing entries, to control the spacing of the output.
The good thing about this technique is that it’s easy to copy the skipping and spacing control characters from the spooled file image to the print control data structure.
Here’s an example. It reads a disk file that was loaded by CPYSPLF and builds a duplicate report.
Fspoolfile if f 136 disk Fqsysprt o f 132 printer oflind(*inof) F prtctl(prtctlds) D prtctlds ds 15 D pSpaceBefore 1 3 D pSpaceAfter 4 6 D pSkipBefore 7 9 D pSkipAfter 10 12 D pLineNbr 13 15 D outputdata s 132 Ispoolfile ns 01 I 1 3 sSkipBefore I 4 4 sSpaceBefore I 5 136 inputdata C read spoolfile C dow not %eof(spoolfile) C eval outputdata = inputdata C if sSkipBefore <> *blanks C eval pSkipBefore = sSkipBefore C else C eval pSkipBefore = *blanks C endif C if sSpaceBefore <> *blanks C eval %subst(pSpaceBefore:3:1) = C sSpaceBefore C else C eval pSpaceBefore = *blanks C endif C except lineout C read spoolfile C enddo C eval *inlr = *on C Oqsysprt e lineout O outputdata 132
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