Parameters

return_code

Return code from IGWASYS. The return code is also returned in register 15. For an explanation, see IGWASYS, IGWASMS, IGWABWO, IGWLSHR Return and Reason Codes. This is an output argument that must be defined as an integer.

reason_code

Reason code from the IGWASYS service. The reason code is also returned in register 0. For an explanation, see IGWASYS, IGWASMS, IGWABWO, IGWLSHR Return and Reason Codes. This is an output argument that must be defined as an integer.

level_indicator

The product whose level information is requested. This is an input argument. Define level_indicator as an integer. Code a value of 1 to request the level of MVS/XA DFP Version 2 or MVS/DFP Version 3 or code a 2 to request the level of DFSMS/MVS or later. This value affects what the system returns in system_level, which is described below.

system_level

The product level that is installed on the system invoking the service. This is an output argument and is a four-element array of integers. The array elements consist of the following integers:

Version number
Release number
Modification level
Special indicator

If you pass a value of 1 for level_indicator, DFSMS returns the system_level values as 3, 3, 2 and 1. The first three values reflect the fact that DFSMS contains the functions of MVS/DFP Version 3 Release 3 modification level 2. The system sets the fourth value to 1 to indicate that the system is actually at a level higher than 3.3.2. If your program were executing on MVS/DFP 3.3.2, then these four values would have been returned as 3, 3, 2 and 0.

If you pass a value of 2 for level_indicator, IGWASYS sets the fourth system_level word to a code that represents the product name that IGWASYS is part of. On no level of the system will this word contain a value that is smaller than on a prior release. One of the following values is returned:

1: “DFSMS/MVS”. With MVS/ESA SP Version 5, it constituted an MVS/ESA system. With OS/390® MVS™, it was part of OS/390 Version 1 or Version 2. The first three system_level words represent DFSMS/MVS.
2: DFSMS is part of OS/390 and not a separate product. The first three system_level words show OS/390 Version 2, Release 10, Modification Level 0, or later. Those words represent the OS/390 level that DFSMS was designed to support. You will see these values also on z/OS® DFSMS Version 1 Release 1 and 2 because DFSMS was not changed from OS/390 2.10.
3: DFSMS is part of z/OS and not a separate product. The first three system-level words show z/OS Version 1, Release 3, Modification Level 0, or later. Those words represent the z/OS level that the DFSMS was designed to support.
>3: DFSMS is part of hypothetical replacement product after all versions and releases of z/OS. The system never returns this value. It represents IBM's intent in case there is such a product. The other words represent the operating system level that the DFSMS was designed to support.

If the next release of the system does not contain a new level of DFSMS, IGWASYS will continue to return the original DFSMS release. This is to help with diagnosis of configuration problems and service.

The intent is that in any future level of the system, your program can determine whether it is running on a particular level or it is running on some later level. If that is what you wish your program to do, then it is suggested that your program test all four words of system level. First test the fourth word to ensure that it has a value of 1 or greater. Then test the other three words to see whether they designate the appropriate version, release and modification level. It is IBM's intent that if one of the values in the first column of the figure below is smaller than was returned for the corresponding value in the prior release, then one of the values in the second column contains a larger value than was returned in the prior release:

Third word (modification level)   Fourth, first or second word
Second word (release)             Fourth or first word
First word (version)              Fourth word

system_attr

System attributes are returned in the system_attr array. This is an output argument. The array elements are defined as follows:

1: Status of the Storage Management Subsystem. A value of 0 indicates inactive; 1 indicates active.
2–4: Reserved elements; 0 is returned.

Define as a four-element array of integers.