Delaying a job for a fraction of a second

Someone asked me if there was a way to pause a job for a fraction of a second. Their colleague had advised them to create a Do-loop that would be performed a certain number of times and that would be "good enough". I was very pleased to learn that the person who asked this question was not satisfied with that answer, and correctly thought that there must be a better way.

I am sure we are all know of the Delay Job command, DLYJOB, but it will only delay a job for whole seconds and not fractions. Fortunately IBM i has two external C functions that can be used to delay a job:

API to check if debug is active

There are some APIs I stumble across and I am left wondering why they were created? The API I will be writing about today, QteRetrieveDebugAttribute, is one of those. This API is used to determine what the debug attribute values are for a job when it is being debugged. I am not going to list which debug attributes they are as it is not relevant to what I am trying to determine. If you are interested in learning what they are click on the link to IBM's documentation at the bottom of this post.

In this example I am just interest to know if the job is being debugged.

I am going to have a procedure within a module call the API, this way I can either bind it into the calling program or included it in a service program, which is my preference. Let me start with the module:

IBM i 7.4 section now in KnowledgeCenter

In January I found signs that a new release of IBM i would happen this year. This week I found another sign when I discovered that the KnowledgeCenter now has a section for IBM i 7.4.

Alas, it is just a "place holder", with no information is within it, but it is another sign of the pending new release.

If you are interested in visiting the new section click here.

Using SQL to check if a batch job is active

A colleague asked me if there was an easy way, using SQL, to tell if a job was active in a subsystem. This subsystem, I am going to call it TESTSBS, should contain two jobs that remain active all day, copying and sending data between various IBM i partitions. During the day-end process the jobs are ended, and then resubmitted after the backups.

Recently there have been problems with these jobs. If one of these jobs errored the system operators would answer the message with "C", which would end the job and the data would not be transferred until someone else noticed. Or the jobs would not end during the day-end process, therefore, after the backups completed two new versions of the job would be submitted resulting in four jobs, two of each.

My colleague had looked into ways of determining which jobs were active in the subsystem. During the day if one of the jobs was missing it could be resubmitted. After the backup finished only if the job was not active would it be submitted. All of the methods she had come up with to determine if the jobs were active were, in her opinion, too complicated. Which is why she came to me.

Copying part of an existing spool file to a new one

I was asked this week how to send the last few pages of a report to a remote output queue. The queue had been configured in a way that even though I could change the range of pages to print, number of copies, etc. despite this a single copy of the entire report would be printed. Such a waste of paper when the report was 450 pages.

The way I overcame this is to create a new spool file, copying data from the original. In a previous post I have shown how to copy multiple spool files and have them print as one. The spool files are copied to a physical file, then the data from the physical file is copied back to a printer file. If I only want a few pages I just need to find the relative record number of the start and end of the section I want to print, and then enter that data when I use the Copy File command, CPYF. For the new spool file to look like the old I also need to know the page width of the original spool file, the characters and lines per inch, CPI and LPI. I can find these myself by looking at the original.

It is not a big deal to do this manually, but my philosophy is if I need to do it more than a few times then it is best to write a program to do it for me. This example program is based upon a program I wrote to do this, make a new spool file that contains a subset of some of the pages from the original spool file, that can then be sent to the remote output queue.