29
Fri, Nov
0 New Articles

TechTip: RPG IV---Are You Having Problems with Your Dates?

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

With RPG IV came a "date" data type, along with a bevy of operations to manipulate it. We added ADDDUR, SUBDUR, and EXTRCT to our programming vocabulary and then figured out how to turn our 6- and 8-digit dates into this new creation. Some shops even converted their database to use date (and time) data types. After some experience with these new operations, we sometimes needed to get dates back into numbers (using MOVE) for required output formatting.

Now, if you are among the proud and few who have ventured into the new world of free-format RPG IV, you may have discovered that the date operation codes are not supported. Likewise, MOVE is not supported (used to convert dates to numbers and vice-versa). And if you are acquiring the current date from the system, using the TIME operation with 12 or 14 digits, forget it. That operation isn't supported either! What's a person to do?

Welcome to the new world of built-in functions for date management. Rather than just rag about it, I will show you examples of these "new" built-in functions and explain how to code using them. Even if you are using extended Factor 2 calculations, you can still use the new built-ins, instead of the operation codes, by use of the EVAL operation.

To add or subtract a duration to/from a date to get a new date (a la ADDDUR and SUBDUR), simply use the plus sign (+) or minus sign (–) operator and one of the %days, %months, or %years built-in functions. For example:

D From_date            S             d        Inz(d'2003-09-16')
D To_date              S             d
D Date3                S             d    
 /free
  To_date = From_date + %months(3);  // To_date value is now 2003-12-16
  Date3  = To_date – %years(7);      // Date3 is now 1996-12-16
 /end-free

Another capability of SUBDUR is subtracting two dates to get duration. This is done in free-form using the %diff built-in as shown in the next example:

D From_date            S             d        Inz(d'2003-09-16')
D To_date              S             d        Inz(d'2009-11-24')
D Difference           S           4   0     
 /free
  Difference = %diff(To_date:From_date:*years); // Difference is now 6
 /end-free

The third parameter of %diff can be *days, *months, or *years (or other values for time and timestamp needs).

Continuing my parallel to the older operations, the built-in function %subdt is used instead of the EXTRCT operation to obtain portions of a date from a date variable. For example:

D From_date            S             d        Inz(d'2003-09-16')
D Month                S            2  0
D Day                  S            2  0
 /free
  Month = %subdt(From_date:*Months);  // Month value is now 9
  Day   = %subdt(From_date:*Days);    // Day value is now 16
 /end-free

You can use the abbreviated form for *Years, *Months, and *Days: *Y, *M, or *D. The %subdt built-in is also useful for obtaining portions from a time or timestamp data type variable.

Obtaining the current date is pretty easy--in fact, a lot easier than the TIME operation. The %date built-in provides for this, as well as converting numbers (packed or character strings) into a date variable. You can use 6- or 8-digit numbers. Knowing or looking up the format code for the order of the numbers helps a bit here. Here are some examples:

D Date1                S             d
D Date2                S             d
D Date3                S             d
D Num6                 S            6  0      Inz(61986)
D Num8                 S            8  0      Inz(12252003)    
 /free
  Date1 = %date(Num6:*MDY); // Date1 becomes date 1986-06-19 from 6 digits
  Date2 = %date(Num8:*USA); // Date2 becomes date 2003-12-25 from 8 digits
  Date3 = %date();          // Date3 becomes the current date from the system
 /end-free

If you're nodding your head and saying, "Sounds pretty easy so far," you're right. But with all this good stuff, you know there has to be some not-so-good stuff. Well, you're right again. Conversion of date data types to decimal is the bugger. Multiple built-ins are needed, and V5R2 is needed for my examples, shown below:

D Date1                S             d        Inz(d'2003-09-16')
D Num6                 S            6  0      
D Num8                 S            8  0          
 /free
  Num6 = %int(%char(Date1:*MDY0)); // The zero after the *MDY removes the
                                   //  punctuation. The %int converts the
                                   //  characters to decimal. *MDY for 6 digits
  Num8 = %int(%char(Date1:*USA0)); // *USA is for 8 digits, with 4 digit year
 /end-free


If you haven't been using these new built-ins for date management, the information above should help you get started.

Jim Martin is corporate technical instructor at Jack Henry & Associates, in Monett, Missouri. He is a veteran of RPG programming, beginning in 1967 with a position at IBM as a Systems Engineer and later was a staff programmer at the Rochester systems programming lab. For eight years, he was at Lakeview Technology as an AS/400 and RPG instructor and was a speaker at various local midrange user group meetings and conferences. He can be reached by email at This email address is being protected from spambots. You need JavaScript enabled to view it..

JIM MARTIN

Jim Martin holds a BS degree in mathematics and an MS in computer science. For 26 years, he was employed by IBM, where he wrote RPG applications for customers and worked in the programming laboratory as a programmer on portions of CPF and the OS/400 operating system. After leaving IBM, Jim took post-graduate work in computer science and performed RPG training. He is an IBM-certified RPG IV developer and author of multiple bestselling editions of Free-Format RPG IV, which, since the book's initial publication in 2005, have taught thousands of RPG IV programmers how to be successful with the free-format coding style.


MC Press books written by Jim Martin available now on the MC Press Bookstore.

Free-Format RPG IV: Third Edition Free-Format RPG IV: Third Edition
Improve productivity, readability, and program maintenance with the free-format style of programming in RPG IV.
List Price $59.95

Now On Sale

Free-Format RPG IV: Second Edition Free-Format RPG IV: Second Edition
>Make the transition from coding in fixed-format RPG to free format.
List Price $59.95

Now On Sale

Functions in Free-Format RPG IV Functions in Free-Format RPG IV
Here’s the ultimate guide to writing RPG IV programs with functions in the free-format style.
List Price $59.95

Now On Sale

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: