• Guru: TryIT – You’ll Like It

  October 2, 2023 Ted Holt

  I have watched children play Whac-a-mole, but I’ve never played it myself, perhaps because the game unpleasantly reminds me of programs that I have had to work on. I fix one bug, only to see another bug rear its ugly little head. Life’s too short to endure such nonsense. Besides, it is embarrassing for someone to tell me that the program I supposedly just fixed is still broken.

  Suppose you’re working on a 4,000-line RPG program and you comment out lines 650-660. What you don’t realize at the time is that a variable used in line 2755 has to …

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• Guru: Procedure Driven RPG With Linear-Main Programs

  September 11, 2023 Gregory Simmons

  A number of years ago, I started migrating away from writing subroutines and started writing procedures instead. Yes, quite often, this was simply because it was “new and shiny” and served no real benefit from their subroutine counterpart. However, as the language and I evolved, I found that my method of approaching every project was what I call procedure driven RPG.

  Let’s have a look at a simple RPG program. In this little program, to give it a purpose, I’m going to have a little fun with math and demonstrate the Fibonacci sequence:

  1	**Free
  
  2	Dcl-s i    Uns(3) Inz(3);
  

  …

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• Guru: Retrieving The Long And Short Object Name

  August 14, 2023 Bob Cozzi

  Many releases ago, IBM i received “Long SQL Names” for files and libraries. These new longer names (up to 128 characters) were well received by SQL enthusiasts, but largely ignored by the mainstream IBM i developer. As each version of IBM i emerged, more and more shops experienced one or more objects with a longer-than-10-character name.

  Recently I created a file named BOAT_TRAFFIC. This name is clearly longer than 10 characters. I used SQL DDL (the CREATE or REPLACE TABLE statement) to create the file. Using SQL DDL is the only real way to create an object with a long …

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• Guru: Object Usage Statistics

  July 10, 2023 Bob Cozzi

  A long time ago in a system far, far away, IBM added the Date Last Used to the Object Description for all objects on the system. The term “last used” means different things to different object types; for *FILE objects it means the file was opened or its description was changed, for *PGM objects it means the program was called, for other objects it generally means what you might think it means (viewed, retrieved/read, updated, etc.) The only exceptions are Device Descriptions which get updated when a *DEVD changes from “Vary On Pending” to some other status.

  The Date Last …

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• Guru: Comparing IFS Directories Using SQL

  June 19, 2023 Mike Larsen

  I use SQL almost every day at my job. It may be just a query in ACS, or it may be embedded SQL in an RPG program. A few days ago, I needed to compare the contents of one IFS directory to another. Combining a few different table functions, I was able to develop a nice solution.

  Note: The code for this article can be downloaded here.

  In this example, I have a directory that has five text files in it. I have a second directory that has three text files in it, and they are the same documents …

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• Guru: Speeding Up RPG By Reducing I/O Operations, Part 2

  June 12, 2023 Gregory Simmons

  Legacy code. Often one admits they have legacy code either with a chuckle or a wince. Nonetheless, it usually is admitted with bad connotations. We must remember though – legacy code becomes legacy code because it works. It performs its tasks day in and day out for many years and is forgotten about. Only the squeaky wheel gets the grease, right?

  The problem with this code is that, while it works, decades slip by, and technology evolves. As these decades roll along, we don’t just end up with a few programs that fit this ‘legacy code’ stereotype, we often end …

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• Guru: Binding Directory Entries

  June 5, 2023 Bob Cozzi

  I assume you’ve heard about *BNDDIR (Binding Directory) objects introduced circa 1994 with OS/400 V3R2. The infamous QC2LE binding directory is used by a huge number of RPG applications to access C runtime and unblocked MI functions such as system cvthc, cpybytes, and matmatr. You have probably seen RPG IV source code with the BNDDIR(‘QC2LE’) keyword on the header specification.

  I was one of the first developers outside of IBM to use Binding Directories for my own code. When I go back and look at my own RPG IV code created prior to mid-2007, well over 90 percent of it …

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• Guru: Watch Out For This Pitfall When Working With Integer Columns

  May 22, 2023 Gregory Simmons

  Remember that awesome jungle game where you had to guide the hero through a series of increasingly hard obstacles to gather treasure? Jumping over snakes, scorpions, and rolling logs, swinging on vines over alligators –your timing had to be just right. Pitfall Harry survived in a world of 255 screens, each of which were 160 x 192 pixels and a dazzling 128 colors! Well today, I want to make you aware of a pitfall which caught me off guard a while back. I hope this article will help you avoid my pitfall.

  There I was, writing my code, happy as …

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• Guru: Find Unused Objects On IBM i Using SQL

  May 15, 2023 Bob Cozzi

  I have a client that uses SQL iQuery for nearly all “Report” type applications since SQL iQuery Version 2. They asked if they could create a report that listed all the unused objects in their user libraries. They also wanted the option to output to Excel-compatible format if desired.

  Since SQL iQuery allows you to output the results of your SELECT statements to any of its supported formats, Excel-compatible is given.

  Note: the code for this article is avaialble on GitHub at this link.

  There were a couple of approaches. I could use our other product, SQL Tools OBJECT_LIST …

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• Guru: Speeding Up RPG By Reducing I/O Operations, Part 1

  May 8, 2023 Gregory Simmons

  Perhaps one of the easiest ways to speed up an RPG program is to reduce the number of I/O operations it needs to perform. In this article let’s explore one simple method for moving toward dataset processing.

  Here I have a simple RPG program. Okay, admittedly, we don’t often get to write “simple” RPG programs, but for this example, I have stripped the RPG program down to just the read loop so I can demonstrate the conversion.

  1     Dcl-f AcctMstr Usage(*Input) Keyed;
  2     Dcl-pr entry ExtPgm('RPGRPT1');
  3       n Packed(3:0);
  4     End-Pr;
  
  5     Dcl-pi entry;
  6       inBranch Packed(3:0);
  7     End-pi;
  
  8     

  …

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