04
Mon, Nov
5 New Articles

TechTalk: Make Your RPG Programs More Flexible

RPG
Typography
  • Smaller Small Medium Big Bigger
  • Default Helvetica Segoe Georgia Times

You can call any RPG program that receives parameters, with or without actually passing parameters to the program - by using the program status data structure and the *PARMS keyword within your I-specs. The program status data structure is set up like any other data structure except you specify an 'S' in column 18. The subfields of the data structure are defined by special keywords. In this case we use the keyword *PARMS (see Figure 1). We assign field name INPARM to contain the value that is returned through the *PARM keyword. Whatever the field name assigned to the *PARM keyword, it will be a three-digit numeric field. It will contain the number of parameters that are passed to your RPG program from the calling program. If the value is zero (no parameters passed), you cannot access the name of the field that is in your *ENTRY-PLIST.

To get around this you can simply check whether the value is zero or not, then take the proper action (such as MOVE *BLANKS) to another field to use in your program. This will bypass the error message 'Reference to unpassed parameter.' This message is saying that you are trying to use a field that you did not receive any data for (and you should have). So you are bypassing the use of the field but you are taking the appropriate action if no parameters were passed. Let's look at an example in 1.

To get around this you can simply check whether the value is zero or not, then take the proper action (such as MOVE *BLANKS) to another field to use in your program. This will bypass the error message 'Reference to unpassed parameter.' This message is saying that you are trying to use a field that you did not receive any data for (and you should have). So you are bypassing the use of the field but you are taking the appropriate action if no parameters were passed. Let's look at an example in Figure 1.

On line 1000 we define the program status data structure. On line 1300 we define the field INPARM for the keyword *PARMS. On line 1500 we define the field PARTNO that we should receive a value in from the calling program. On line 1700 we check INPARM to see if we were passed a parameter and if we were, we move it into SCPART to be used in our program. If we were not passed a parameter, INPARM will have a value of zero and we will move blanks into SCPART.

If INPARM is zero, the program will never execute statement 2000 and we will not receive the message 'Reference to unpassed parameter'. This way the program will run perfectly.

You can use this for programs that are looking for any number of parameters to be passed or you can do any processing that you wish based on the value of INPARM (as long as you do not use the field name of the variable for which you did not receive data).

We have used this technique for all of our inquiry programs. They can be called from a menu (without parameters), from another RPG program (to select and return parameters), or from a CL program. We have found that we can use this technique to eliminate the need for many three-line CL programs that do nothing more than CALL the RPG program and pass a blank parm to it. So you can cut down on the number of CL programs, and make your RPG programs more flexible at the same time. Plus you can have one RPG program handle both your viewing data function and selecting data function.

Bruce Knoll Kentwood, Michigan


TechTalk: Make Your RPG Programs More Flexible

Figure 1 RPG program accessing parameter count

 Figure 1: RPG Program Accessing Parameter Count .... ....1.... ....2.... ....3.... ....4.... ....5.... ....6.... ....7 1000 ISDS SDS 1100 I 244 253 WSID 1200 I 254 263 USER 1300 I *PARMS INPARM 1400 C *ENTRY PLIST 1500 C PARM PARTNO 5 1600 C* 1700 C INPARM IFEQ 0 1800 C MOVE *BLANKS SCPART 5 1900 C ELSE 2000 C MOVE PARTNO SCPART 2100 C END 2200 C* .... ....1.... ....2.... ....3.... ....4.... ....5.... ....6.... ....7 
BLOG COMMENTS POWERED BY DISQUS

LATEST COMMENTS

Support MC Press Online

$

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: