===========================================================================
* IBM Open XL Fortran for AIX 17.1.0 
* 5765-J19; 5725-C74
*
* Copyright IBM Corp. 2021
* Licensed Materials - Property of IBM
*
* US Government Users Restricted Rights - Use, duplication or
* disclosure restricted by GSA ADP Schedule Contract with IBM Corp.
*
* AIX, IBM, the IBM logo, and ibm.com are trademarks or registered 
* trademarks of International Business Machines Corp., registered in many 
* jurisdictions worldwide. Other product and service names might be 
* trademarks of IBM or other companies. A current list of IBM trademarks 
* is available on the Web in the Copyright and trademark information section 
* (www.ibm.com/legal/copytrade.shtml).
*
* Other company, product, or service names might be trademarks or service
* marks of others.
===========================================================================

This README file contains the latest information about Open XL Fortran for
AIX 17.1.0.

The Japanese version of the README files is available at:
https://www.ibm.com/support/pages/node/592873

By using Open XL Fortran for AIX 17.1.0, you agree to the terms of the license
as specified in the following files, which are located in the root directory 
of the distribution package: 

* LicenseAgreement.pdf
* license.pdf

These license files can be found in the /opt/IBM/openxlf/17.1.0/ directory after 
basic installation.

You need a PDF viewer to view these files.

The Open XL Fortran for AIX 17.1.0 product offers three license types: Authorized 
User, Concurrent User, and monthly license. For additional license 
information, see the Open XL Fortran for AIX 17.1.0 announcement  
(http://www.ibm.com/common/ssi/cgi-bin/ssialias?subtype=ca&infotype=an
&supplier=897&letternum=ENUS221-322) and the License Information document.


This document contains the following sections:

1. Online product documentation
2. Installation information
3. Known limitations for Open XL Fortran for AIX 17.1.0
4. Support information


1. Online product documentation
===============================

Information about installing and using Open XL Fortran for AIX 17.1.0 can be
found in the online product documentation  
(https://www.ibm.com/docs/openxl-fortran-aix/17.1.0) or on the Open XL 
Fortran library page (https://www.ibm.com/support/pages/node/592873).


2. Installation information
===========================

Operating System Support
------------------------

Open XL Fortran for AIX 17.1.0 is supported on the following operating
systems:

* IBM AIX 7.2 TL5 SP3


Uninstalling previous versions
------------------------------

Installing this version of the compiler does not remove or change 
previous versions of the compiler, only the C++ runtime library, the 
Fortran runtime library, and the SMP runtime library are migrated 
to the new versions. This was achieved by differentiating the 
installation fileset names from those of the previous versions, 
including the version, release and modification level (V.R.M) in the 
name, and installing to new locations that include V.R.M in the 
installation paths.

Installation instructions
-------------------------

The installation path is:
/opt/IBM/openxlf/17.1.0/

To install the compiler, run the following command:
	
installp -aXYgd ./usr/sys/inst.images -e /tmp/install.log all
	
Language filesets for locales that you do not have on your machine 
will fail to install. If you require those languages, install the 
locale support from the OS installation media and reinstall the compiler.

To add the compiler invocations to your path, run the following 
command:

export PATH=/opt/IBM/openxlf/17.1.0/bin/:$PATH

See the "IBM Open XL Fortran for AIX 17.1.0 Installation Guide" for 
more installation instructions.


3. Known limitations for Open XL Fortran for AIX 17.1.0
=======================================================

* Debug information generation (-g) does not work for advanced
  language features.

* Procedure pointers to internal procedures are not compatible 
  with those from IBM XL Fortran for AIX 16.1.0. The implementation 
  of procedure pointers to internal procedures might change again 
  in the future.

* Static initialization of very large arrays is slow and may cause
  the compiler to run out of memory.
  For example, if you have code like:
        real :: array(2**24) = 1.0
  The compiler will take a very long time to complete compilation, 
  and will require a lot of memory. You can work around this issue 
  by initializing at run time instead:
          real, save :: array(2**24)
          logical, save :: array_is_initialized = .false.
          if (.not. array_is_initialized) then
                array = 1.0
                array_is_initialized = .true.
          endif

* The maximum supported stack size is 2 GB.


4. Support information
======================

The following site contains support information for the Open XL Fortran for
AIX 17.1.0 product:

  https://ibm.biz/openxlf-support

