In the past, I have written a couple of TechTips about some of the APIs I use frequently (TechTip: Using the QTMMSENDMAIL API and TechTip: Getting the IP Address of a Workstation Device). But what about the others? With that thought, I decided to compile my own "Top 10" list of APIs. It turned out not be as simple as I had expected.
To start with, when I started researching to find the "best" APIs, I ended up learning some new ones. Did you know that there is not just one but several random-number-generator APIs? I didn't. Or did you know that there are functions to return the day of the week for a given Lilian date? What the heck is a Lilian date? The good news is that there is also an API to convert standard dates to Lilian dates. Have you ever wondered how the file editor programs (e.g., DBM, DFU, etc.) managed to create those displays without knowing the file structure ahead of time? Here's your answer: There is a whole group of APIs for handling display input and output without using a display file (Dynamic Screen Manager APIs ).
Once I was able to reel myself in from reading about all the APIs I had never known about, I was able to get down to making the list. I wanted to limit my list to just 10. The problem was that some of the most useful APIs come in groups. All of the List APIs, for example, are really handy. These include some really useful stuff: list spool files, list objects, list jobs, etc. And what about the User Space APIs? Heck, you can't even use the List APIs without using a user space. Speaking of the User Space APIs, now that we have the ability to use pointers in RPG, some of the User Space APIs are pretty much obsolete--the Retrieve User Space API (QUSRTVUS) for example.
With that said, I'll cut to the chase. Here is the Top 10 API list (IMHO, of course).
1. QCMDEXC or QCAPCMD---Execute a CL command. This is the first one I learned to use and perhaps still the most widely used API out there. QCAPCMD extends the abilities of QCMDEXC but accomplishes essentially the same thing.
2. User Space APIs--Yes, I know I said some of these were obsolete, but the others are necessities. I couldn't separate them because you really need to be able to create one, get the pointer to it, and eventually delete it. Also, as I mentioned, many of the other useful APIs depend on user spaces.
3. QRTVOBJD--I use the Retrieve Object Description API in almost every single command I ever create.
4. List APIs--Again, all these are together because I use them so frequently. I have used the List Spool API to create automatic spool file cleanup programs, programs to find out which spool files or objects are using up the most disk space, and spool file archiving programs. (You'll need to access the List APIs from the alphabetic API list. Scroll down to "L.")
5. QTMMSENDMAIL--If you need to send an email to more than one recipient or with more than one attachment, SNDDST will not help you. This API will.
6. HTTP APIs--I almost forgot about these. Since I started using C for all my CGI-type applications, I don't use them anymore. But if you are using the AS/400 as a Web server and using RPG, then this group of APIs should be near the top of your list.
7. QUSCMDLN--I was so happy to discover the Display Command Window API. After that, I didn't have to rig up my own "command window" using QCMDEXC.
8. QMHRTVM--I almost forgot about this one, too. But anyone who uses subfile messaging and/or has to support multiple languages will appreciate the Retrieve Message API.
9. QGYGTLE--I couldn't very well leave the Get List Entries API off the list (no pun intended). After all, creating a list of jobs or objects is all well and good, but it's not worth much unless you can retrieve the entries. You'll also need the associated Open List API.
10. Debug APIs--I nearly left these off the list because I haven't actually used them much. But I once deleted a program source member (thinking I had a copy somewhere else) and then realized that I was left with a program object and no source code. These APIs enabled me to recover the ILE source code from the object...and probably saved me from having to find a new line of work.
Well, that's it. As you can probably tell, I sort of fudged the list because I couldn't narrow it down to just 10. I'll bet you can't either. I would encourage everyone to do the exercise that I did and just look through all the available APIs, either by browsing IBM's API page or by reading iSeries and AS/400 APIs at Work. You may find some new tools. I certainly did.
By the way, a Lilian date is the number of days elapsed since October 14, 1582 (of course!?).
Jeff Olen is a member of the AS/400 development team at Gauss Interprise, a content management software company located in Irvine, California. He can be reached by email at
Jeff Olen is a super-spy now but keeps his cover identity intact by working for video game studios on the East Coast. So when he’s not out killing members of ISIS or rescuing refugees, you can find him playing Wolfenstein II or testing the new Fallout 76 releases at his beach house in Costa Rica. In any case, he can’t be reached. You can email his cat at
MC Press books written by Jeff Olen available now on the MC Press Bookstore.
 |
||
 |
|
The IBM i Programmer’s Guide to PHP Get the scoop on how PHP can—and should—be deployed on IBM systems. List Price $79.95 Now On Sale
|
More 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.
TRY 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.
Forms 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.
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:
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.
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:
LATEST COMMENTS
MC Press Online