Fri, Jun
4 New Articles

More Free-Form for RPG, Part 3

  • Smaller Small Medium Big Bigger
  • Default Helvetica Segoe Georgia Times
Seems like folks can't get enough of the free-form control statements replacement for specs in RPG. Or maybe it's just that everyone who writes wants to talk about it. But this is all I'll say about it, so at least be glad about that.


So far, we've covered free-format control statements and H control statements (Part 1), and file control statements (Part 2). What's left? Just data structure control statements, and the PI and PR control statements used for prototyping. So let's jump in.


By this time, if you've read the previous two installments, you know that things start not with a D in column 7 but with the data structure control keyword somewhere in columns 8–80.




This will then be followed by the data structure name and whatever keywords might be required:


dcl-ds Product_rec likerec(PMP100);        


Or if you like to leave a bit of space, do this:


dcl-ds     Product_rec     likerec(PMP100);


You can define a number of things here, and each has a slightly different control statement keyword. But one thing that's true in all situations is that the ellipses that we can use in D-specs are not valid in data structure control statements.

Named Constants

The first things you can define are named constants. This is done with the dcl-c keyword, versus the dcl-ds keyword. Once the constant is defined, you can use it in your program. And I honestly don't know why I said that. Sort of stands to reason, doesn't it?


Below is a good example of how you use named constants and mix the file and data structure control statements. And it also shows how you don't necessarily need to have the file control statements first. Why would you do this? Well, it allows you to then refer to the file as the Product_Master elsewhere in your program rather than MSPMP100.


            dcl-c       Product_Master         'MSPMP100';

            dcl-f     product_master     output       printer 





Just an option. Not a rule.

Standalone Field

You can also define standalone fields. Start with dcl-ds, and end with a semicolon (;).


If you do name the data structure field, and most of the time you will, then that comes next.


If you decide to not name it, you can just use the symbol '*N'. Not sure why you would not want to name it, but I'm sure some people would think if the field were not very important, if it were just intermediary in nature, then maybe you shouldn't name it. I don't care for that, but I'm continually amazed by how many people don't check with me before doing stuff. Even important things like naming variables.


After the name (or *N), then we get the keywords. Are you beginning to see the pattern here?


The first keyword must be either LIKE or the data type and length. That is,


dcl-s name LIKE(other_name);



dcl-s order_number packed(6:0) inz(0);




dcl-s next_order_number LIKE(order_number: +1);


dcl-s next_order_number           Like(order_number: +1);



The end-ds is not used for LIKEDS or LIKEREC. You can code the data structure name on the END-DS for documentation purposes, and if there are no standalone fields, you can put the end-ds on the same line as the dcl-ds.


This is a small point but an important one, and it deserves a section of it's own. Ready? Brace yourselves. The overlay keyword is now supported only in specific situations.


Specifically, you can only use it to overlay subfields. It cannot be used to overlay the entire data structure. Now remember; this is only when you're using the data structure control statements. And there's no support at all for the Overlay(ds:*next) because that means there's no set positionjust put it after the last field in the data structure, so that's meaningless. Since you can intermix the new control statements with the old D-specs, you could still use the Overlay on the D-spec. Personally, I don't have a problem with saying goodbye to the big overlay. As far as I'm concerned, that's a holdover from the days when every bit of memory had to be weighed and measured. That's not the case today. Overlays help hide what's going on as you move from one field to another, and I'm not at all sorry to see them restricted. We tend to hold on to things long after they have outlived their real purpose. But that's just me.


Technically, subfields should start with a dcl-subf, but it's required only if the name of the subfield is the same as a free-form op code, like write or eval.


If the subfields need to be positioned, use the POS(99) keyword to indicate where that subfield starts. It replaces the fixed-format from and to values.


And you know what I believe? If you have subfields, then you must include the end-ds.

PR and PI

As you probably know, the PR and PI structures are usedespecially in /Free (but also in regular RPG)along with the P-spec to support the CALLP prototyping call statement. Things for the PI and PR specs are done the same way as DS'es. And the end-pi/end-pr is required.


dcl-pr dws0176 extpgm;

      parm1 char(256);

      parm2 packed(10:3);   




dcl-pi          dws0170;

               parm1 char(256);

                parm2 packed(10:3);




On the PI, if there's no name for the group, you can use '*n' just as you can for data structures.


On the PR, the 'extpgm' keyword is optional, and if you don't code it, the compiler will default to using the name of the PR group as the program name being called. But this is only if the program name is 10 characters or less'"'".


Also on the PR group, if the program you're calling has a mixed-case name, you need to use the 'extproc' keyword, like so:


dcl-pr         EL3write          extproc('EL3write');


Or you could use the *dclcase to avoid retyping the name:


dcl-pr EL3write extproc(*dclcase);


This can sometimes help prevent typo errors if you have several programs you're calling that have similar names and you copy lines but forget to change the name in the extproc keyword. Or you can stop using mixed-case, weirdo names that you can easily screw up. Your choice.


Finally, we get to the procedures syntax in free-format. In spec language, these are defined by a P-spec, but using the new free-form format, it starts with a dcl-proc with a procedure name and keywords and ends with the end-proc (the procedure name on the end-proc is optional).


dcl-proc        procedure-name    keywords;


end-proc        procedure-name;



It took a while, but I think we've worked our way through the free-form enhancements for 7.1   And that's a key thing to remember. These are enhancements that are only for 7.1. If you're not on 7.1, fahgettaboudit. It's only for the cool kids. Yep, it's just like in high school. The cool kids get everything. But if you're not on 7.1, then this should encourage you in that direction. Moving forward is always a good thing.

David Shirey

David Shirey is president of Shirey Consulting Services, providing technical and business consulting services for the IBM i world. Among the services provided are IBM i technical support, including application design and programming services, ERP installation and support, and EDI setup and maintenance. With experience in a wide range of industries (food and beverage to electronics to hard manufacturing to drugs--the legal kind--to medical devices to fulfillment houses) and a wide range of business sizes served (from very large, like Fresh Express, to much smaller, like Labconco), SCS has the knowledge and experience to assist with your technical or business issues. You may contact Dave by email at This email address is being protected from spambots. You need JavaScript enabled to view it. or by phone at (616) 304-2466.

MC Press books written by David Shirey available now on the MC Press Bookstore.

21st Century RPG: /Free, ILE, and MVC 21st Century RPG: /Free, ILE, and MVC
Boost your productivity, modernize your applications, and upgrade your skills with these powerful coding methods.
List Price $69.95

Now On Sale



Support MC Press Online

$0.00 Raised:

Book Reviews

Resource Center

  • SB Profound WC 5536 Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application. You can find Part 1 here. In Part 2 of our free Node.js Webinar Series, Brian May teaches you the different tooling options available for writing code, debugging, and using Git for version control. Brian will briefly discuss the different tools available, and demonstrate his preferred setup for Node development on IBM i or any platform. Attend this webinar to learn:

  • SB Profound WP 5539More than ever, there is a demand for IT to deliver innovation. Your IBM i has been an essential part of your business operations for years. However, your organization may struggle to maintain the current system and implement new projects. The thousands of customers we've worked with and surveyed state that expectations regarding the digital footprint and vision of the company are not aligned with the current IT environment.

  • SB HelpSystems ROBOT Generic IBM announced the E1080 servers using the latest Power10 processor in September 2021. The most powerful processor from IBM to date, Power10 is designed to handle the demands of doing business in today’s high-tech atmosphere, including running cloud applications, supporting big data, and managing AI workloads. But what does Power10 mean for your data center? In this recorded webinar, IBMers Dan Sundt and Dylan Boday join IBM Power Champion Tom Huntington for a discussion on why Power10 technology is the right strategic investment if you run IBM i, AIX, or Linux. In this action-packed hour, Tom will share trends from the IBM i and AIX user communities while Dan and Dylan dive into the tech specs for key hardware, including:

  • Magic MarkTRY the one package that solves all your document design and printing challenges on all your platforms. Produce bar code labels, electronic forms, ad hoc reports, and RFID tags – without programming! MarkMagic is the only document design and print solution that combines report writing, WYSIWYG label and forms design, and conditional printing in one integrated product. Make sure your data survives when catastrophe hits. Request your trial now!  Request Now.

  • SB HelpSystems ROBOT GenericForms of ransomware has been around for over 30 years, and with more and more organizations suffering attacks each year, it continues to endure. What has made ransomware such a durable threat and what is the best way to combat it? In order to prevent ransomware, organizations must first understand how it works.

  • SB HelpSystems ROBOT GenericIT security is a top priority for businesses around the world, but most IBM i pros don’t know where to begin—and most cybersecurity experts don’t know IBM i. In this session, Robin Tatam explores the business impact of lax IBM i security, the top vulnerabilities putting IBM i at risk, and the steps you can take to protect your organization. If you’re looking to avoid unexpected downtime or corrupted data, you don’t want to miss this session.

  • SB HelpSystems ROBOT GenericCan you trust all of your users all of the time? A typical end user receives 16 malicious emails each month, but only 17 percent of these phishing campaigns are reported to IT. Once an attack is underway, most organizations won’t discover the breach until six months later. A staggering amount of damage can occur in that time. Despite these risks, 93 percent of organizations are leaving their IBM i systems vulnerable to cybercrime. In this on-demand webinar, IBM i security experts Robin Tatam and Sandi Moore will reveal:

  • FORTRA Disaster protection is vital to every business. Yet, it often consists of patched together procedures that are prone to error. From automatic backups to data encryption to media management, Robot automates the routine (yet often complex) tasks of iSeries backup and recovery, saving you time and money and making the process safer and more reliable. Automate your backups with the Robot Backup and Recovery Solution. Key features include:

  • FORTRAManaging messages on your IBM i can be more than a full-time job if you have to do it manually. Messages need a response and resources must be monitored—often over multiple systems and across platforms. How can you be sure you won’t miss important system events? Automate your message center with the Robot Message Management Solution. Key features include:

  • FORTRAThe thought of printing, distributing, and storing iSeries reports manually may reduce you to tears. Paper and labor costs associated with report generation can spiral out of control. Mountains of paper threaten to swamp your files. Robot automates report bursting, distribution, bundling, and archiving, and offers secure, selective online report viewing. Manage your reports with the Robot Report Management Solution. Key features include:

  • FORTRAFor over 30 years, Robot has been a leader in systems management for IBM i. With batch job creation and scheduling at its core, the Robot Job Scheduling Solution reduces the opportunity for human error and helps you maintain service levels, automating even the biggest, most complex runbooks. Manage your job schedule with the Robot Job Scheduling Solution. Key features include:

  • LANSA Business users want new applications now. Market and regulatory pressures require faster application updates and delivery into production. Your IBM i developers may be approaching retirement, and you see no sure way to fill their positions with experienced developers. In addition, you may be caught between maintaining your existing applications and the uncertainty of moving to something new.

  • LANSAWhen it comes to creating your business applications, there are hundreds of coding platforms and programming languages to choose from. These options range from very complex traditional programming languages to Low-Code platforms where sometimes no traditional coding experience is needed. Download our whitepaper, The Power of Writing Code in a Low-Code Solution, and:

  • LANSASupply Chain is becoming increasingly complex and unpredictable. From raw materials for manufacturing to food supply chains, the journey from source to production to delivery to consumers is marred with inefficiencies, manual processes, shortages, recalls, counterfeits, and scandals. In this webinar, we discuss how:

  • The MC Resource Centers bring you the widest selection of white papers, trial software, and on-demand webcasts for you to choose from. >> Review the list of White Papers, Trial Software or On-Demand Webcast at the MC Press Resource Center. >> Add the items to yru Cart and complet he checkout process and submit

  • Profound Logic Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application.

  • SB Profound WC 5536Join us for this hour-long webcast that will explore:

  • Fortra IT managers hoping to find new IBM i talent are discovering that the pool of experienced RPG programmers and operators or administrators with intimate knowledge of the operating system and the applications that run on it is small. This begs the question: How will you manage the platform that supports such a big part of your business? This guide offers strategies and software suggestions to help you plan IT staffing and resources and smooth the transition after your AS/400 talent retires. Read on to learn: