Programs in Use tells you when programs are active within the call stack of open jobs. There are many situations when you would want to know this, but unfortunately OS/400 provides no easy way to find this out -- called programs are not locked so you are not able to tell when a program is being run or which jobs are using it.

People are TOLD - do not be in shipping while the billing is running. But how do you KNOW the billing is running? There are other examples of the same kind of thing. You cannot get into this order because it is in a particular kind of state -- well who is on-line right now doing the kind of work that puts it into that state?

Who's doing what?

Find who's calling a program. The WRKPGMINU command returns information about a single program, generic program/library, or all programs and libraries. The All Programs mode gives you an overview of who's signed on and what they're doing. See the screen shots.

APIs - call these from your application programs.

This tool also has two Application Program Interface (API) programs that can return information for your applications.

API #1 - see if a program is being used.

This API will pass back information on whether a program is being used. It can return either a Yes / No flag to say whether a program is active, or a list of jobs which are using that program.

E.g. suppose that an 'Invoice Run' program is not allowed to be used by more than one user at a time. How do you check for such use? A common method is to flag a byte in a data-area. But if the Invoice Run falls over that flag stays set and must be switched off manually. And if the program is being used, then how will a user know who is using it? This API can return such information for you to display on their screens.

API #2 - retrieve call stack.

This API will retrieve the call stack (invocation stack) of any job. This sought-after function is strangely absent in OS/400*. A qualified job name (name+user+number) is sent to the API and the call stack is returned in an array (no user spaces required). It works at all security levels.

A good feature of this API is that it allows you to retrieve the stack backwards, i.e. most recent program first. Why backward? Because most the time all you are interested in is the name/library of your current program or the program which called it. So with this feature you won't need to cater for array processing. See the below screen shots.

See some Screen Shots (including code examples)
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Shareware price:
$150 USD**

This software is provided as shareware. It is supplied on the condition that if it were to be used on an ongoing basis or for a commercial purpose, that it be purchased in accordance with the prices, terms and payment methods set out in the accompanying documentation.

* This function has now become available in V5R1 via API: QWVRCSTK. This product's API#2 is still useful for prior releases, and also works on V5R1.
** Prices are subject to change without notice unless previously agreed to.