29
Fri, Nov
0 New Articles

TechTalk: Handling Function Keys in RPG/400

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

Here is a method, in your RPG program, to check which function key was used on a screen, without using any indicators.

The usual method is to code your DDS including keywords like CF03(03) and ROLLUP(15), and have your RPG program check the status of indicators 03 and 15. Another method (at least for F1-F24) is to use the KA-KY indicators. Here is a different technique that requires no indicators at all, and can positively check for the Enter key being pressed, instead of assuming that it was pressed because none of the indicators associated with function keys were on. With this technique, you code your DDS for the display file without response indicators: CF03, ROLLUP, and so on.

A workstation file can have an information data structure associated with it (coded with a K-continuation on the F-spec). This data structure contains a byte in position 369 called the Attention Indicator (AID) Byte. After a screen is read, it tells which function key was pressed, including F1-F24, Roll keys, Clear, Help, Home or Enter key. This is in the RPG/400 Reference manual (Chapter 2), and the Data Management Guide (Appendix A).

Using the AID byte is great because it eliminates the need for any indicators, and the Enter key itself can be checked for. The RPG program logic can be set up in a nice CASE structure (or SELECT/WHEN/OTHER). An additional benefit is being able to check for an invalid function key being pressed. That might happen if your DDS accidentally allows a function key, which your RPG program does not expect (maybe you copied DDS source and erroneously included an extra function key).

See 1, Sample RPG Program. You need to code a K-continuation line on your workstation F-spec: KINFDS DSPDS. INFDS is the keyword for information data structure, and DSPDS is the name I chose for my data structure. Create a data structure with that name, and define subfield AID as one-byte long, at position 369. After you have read a screen, call the external program AID2FKEY, shown in 2. The first parameter is the AID byte and the second parameter is an 8-character field that contains the name of the function key. The possible values returned are: F1, F2, ..., F24, ENTER, CLEAR, HELP, ROLLDOWN, ROLLUP, PRINT, HOME, AUTOENT and INVALID.

See Figure 1, Sample RPG Program. You need to code a K-continuation line on your workstation F-spec: KINFDS DSPDS. INFDS is the keyword for information data structure, and DSPDS is the name I chose for my data structure. Create a data structure with that name, and define subfield AID as one-byte long, at position 369. After you have read a screen, call the external program AID2FKEY, shown in Figure 2. The first parameter is the AID byte and the second parameter is an 8-character field that contains the name of the function key. The possible values returned are: F1, F2, ..., F24, ENTER, CLEAR, HELP, ROLLDOWN, ROLLUP, PRINT, HOME, AUTOENT and INVALID.

I suggest using a nice CASE structure (or SELECT/WHEN/OTHERWISE) which includes all allowable function keys, the Enter key, and a catch-all for any invalid keys. If that doesn't fit in well with your existing program structure, just change from testing indicators to testing the return parameter (for example, FKEY IFEQ 'F3').

Editor's Note: Notice how the binary AID byte is converted to decimal in program AID2FKEY. AID is passed as a character parameter, moved to the low order byte (BYTE2) of the two-byte data structure, BINARY. BIN4 now contains the decimal equivalent of the binary byte AID. The key to the technique is the two-byte binary field (BIN4) defined over the two character fields, BYTE1 and BYTE2.


TechTalk: Handling Function Keys in RPG/400

Figure 1 Sample RPG program

 Figure 1: Sample RPG Program ....+....1....+....2....+....3....+....4....+....5....+....6....+....7 FDSPFILE CF E WORKSTN F KINFDS DSPDS * IDSPDS DS I 369 369 AID * C EXFMTRECORD * C CALL 'AID2FKEY' C PARM AID C PARM FKEY 8 * C FKEY CASEQ'ENTER' ENTER C FKEY CASEQ'F3' EXIT C FKEY CASEQ'F4' LIST C FKEY CASEQ'F12' CANCEL C FKEY CASEQ'F24' MOREKY C FKEY CASEQ'HELP' HELP C FKEY CASEQ'ROLLUP' ROLLUP C FKEY CASEQ'ROLLDOWN'ROLLDN C CAS INVALD C END ....+....1....+....2....+....3....+....4....+....5....+....6....+....7 
TechTalk: Handling Function Keys in RPG/400

Figure 2 RPG program AID2FKEY

 Figure 2: Program AID2FKEY ....+....1....+....2....+....3....+....4....+....5....+....6....+....7 E TABKEY 1 32 4 0 TABDSC 8 * IBINARY DS I B 1 20BIN4 I 1 1 BYTE1 I 2 2 BYTE2 * C *ENTRY PLIST C PARM AID 1 C PARM FKEY 8 * C CLEARBIN4 C MOVE AID BYTE2 * C BIN4 LOKUPTABKEY TABDSC 31 C CLEARFKEY C *IN31 IFEQ '1' C MOVELTABDSC FKEY C ELSE C MOVEL'INVALID' FKEY C END * C RETRN ** Table of Function Key Values 0049F1 0050F2 0051F3 0052F4 0053F5 0054F6 0055F7 0056F8 0057F9 0058F10 0059F11 0060F12 0063AUTOENT 0177F13 0178F14 0179F15 0180F16 0181F17 0182F18 0183F19 0184F20 0185F21 0186F22 0187F23 0188F24 0189CLEAR 0241ENTER 0243HELP 0244ROLLDOWN 0245ROLLUP 0246PRINT 0248HOME ....+....1....+....2....+....3....+....4....+....5....+....6....+....7 To compile: CRTRPGPGM PGM(xxx/AID2FKEY) SRCFILE(xxx/QRPGSRC) 
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: