RPGLE Program Writing to a Printer File

Learning Objective

By the end of this lesson, you will be able to declare a printer file in free-format RPGLE using dcl-f, and use WRITE to print a specific record format.

Simple Explanation

A printer file is declared in free-format RPGLE using dcl-f, the same keyword used for database and display files, with the device type printer identifying it as a printer file.

dcl-f CUSTRPTP printer;

dcl-s custNbr packed(6:0);
dcl-s custName char(30);
dcl-s custBal packed(9:2);

custNbr = 1042;

exec sql
  select CUSTNAME, CUSTBAL into :custName, :custBal
  from CUSTMAST
  where CUSTNBR = :custNbr;

write HDGFMT;

if sqlcode = 0;
  write DTLFMT;
endif;

Here, dcl-f CUSTRPTP printer; declares CUSTRPTP as the printer file this program writes to, using the heading and detail record formats, HDGFMT and DTLFMT, covered in the Report Record Formats lesson. write HDGFMT; prints the heading line, and write DTLFMT; prints one detail line using whatever values are currently in the fields that DTLFMT shares with the RPGLE program, such as custName and custBal retrieved above.

Why It Matters

WRITE is the same operation already covered for adding a new record to a physical file in the Writing Records with WRITE lesson; here it means something different again: printing one line to a printer file, using whichever record format is named. Recognizing that WRITE behaves differently depending on the kind of file it targets, physical, display, or printer, is essential for reading RPGLE code correctly.

Practical Example

Imagine the daily customer balance report described throughout this lesson group. The program declares CUSTRPTP as its printer file, writes HDGFMT once to print the report's title and column headings, then, for each customer retrieved, writes DTLFMT to print that customer's number, name, and balance as one line on the report.

This is a simplified, illustrative example rather than a specific real program, but it reflects the core pattern behind how an RPGLE program actually produces a printed report.

Common Confusions

"Is this the same WRITE operation covered for physical files?" It is the same RPGLE operation name, WRITE, but it behaves differently depending on the file it targets. On a physical file, WRITE adds a new stored record, as covered in the Writing Records with WRITE lesson. On a printer file, WRITE prints one line using the named record format.

"Does writing HDGFMT and DTLFMT in this order guarantee the heading prints before the detail line?" Yes, within a single program's flow: RPGLE statements execute in the order written, so write HDGFMT; printing before write DTLFMT; in the code means the heading line appears before the detail line on the report.

"Can a printer file be declared alongside a database file in the same program, like CUSTRPTP and CUSTMAST here?" Yes. A single RPGLE program can declare more than one file, of different kinds, at the same time, exactly as this lesson's example works with both a database file, accessed here through embedded SQL, and a printer file together.

Quick Recap

• dcl-f fileName printer; declares a printer file in free-format RPGLE.
• WRITE recordFormat; prints one line to the printer file, using the named record format.
• WRITE behaves differently depending on the file it targets: adding a stored record for a physical file, versus printing a line for a printer file.
• A single RPGLE program can declare and use a printer file alongside a database file at the same time.

Try Asking the AI Tutor

Use the AI Tutor to ask follow-up questions about this lesson. For example, try asking:

• "What happens if I write DTLFMT without ever writing HDGFMT first?"
• "Can a printer file's fields be filled in using native RPGLE file I/O instead of embedded SQL?"