Engineering and Scientific Subroutine Library for AIX Version 3 Release 3: Guide and Reference

IESSL--Determine the Level of ESSL Installed

This function returns the level of ESSL installed on your system, where the level consists of a version number, release number, and modification number, plus the fix number of the most recent PTF installed.

Syntax

On Return

Function value

 

is the level of ESSL installed on your system. It is provided as a fullword integer in the form vvrrmmff, where each two digits represents a part of the level:

• vv is the version number.
• rr is the release number.
• mm is the modification number.
• ff is the fix number of the most recent PTF installed.

Returned as: a fullword integer; vvrrmmff > 0.

Notes

1. To use IESSL effectively, you must install your ESSL PTFs in their proper sequential order. As part of the result, IESSL returns the value ff of the most recent PTF installed, rather than the highest number PTF installed. Therefore, if you do not install your PTFs sequentially, the ff value returned by IESSL does not reflect the actual level of ESSL.
2. Declare the IESSL function in your program as returning a fullword integer value.

Function

The IESSL function enables you to determine the current level of ESSL installed on your system. It is useful to you in those instances where your program is using a subroutine or feature that exists only in certain levels of ESSL. It is also useful when your program is dependent upon certain PTFs being applied to ESSL.

Example

This example shows several ways to use the IESSL function. Most typically, you use IESSL for checking the version and release level of ESSL. Suppose you are dependent on a new capability in ESSL, such as a new subroutine or feature, provided for the first time in ESSL Version 3. You can add the following check in your program before using the new capability:

   IF IESSL() >= 3010000

By specifying 0000 for mmff, the modification and fix level, you are independent of the order in which your modifications and PTFs are installed.

Less typically, you use IESSL for checking the PTF level of ESSL. Suppose you are dependent on PTF 2 being installed on your ESSL Version 3 system. You want to know whether to call a different user-callable subroutine to set up your array data. You can add the following check in your program before making the call:

   IF IESSL() >= 3010002

If your system support group installed the ESSL PTFs in their proper sequential order, this test works properly; otherwise, it is unpredictable.