CGNS version 3.4.2

Overview: This release addresses an issue in the 3.4.1 release, which incorrectly indicates the CGNS files were generated by CGNS version 3.4.0. This causes incompatibility with CGNS version 4.1.2.

All users of version 3.4.1 should upgrade to 3.4.2. The 3.4.1 release is removed, and the details of why 3.4.1 was released were added to these release notes.

INTRODUCTION

This document describes the difference between CGNS 3.4.1 and
CGNS 3.4.2 and contains information on known problems in
CGNS 3.4.2.

Links to the CGNS current released source code can be found at:

http://cgns.org/download.html

User documentation for the current release can be found at:

http://cgns.org/CGNS_docs_current/midlevel/index.html

For more information, see the CGNS home page:

http://cgns.org

CONTENTS

• New Features
• Support for new platforms and languages
• Bug Fixes since CGNS 3.4.1
• Known Problems

New Features

Configuration:
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Library:
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Parallel Library:
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Fortran Library:
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Tools:
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Bug Fixes since CGNS 3.4.1 release

Library:
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 * (CGNS-236) Fixed the CGNS library versioning internals. Release 3.4.1 removed.

ISSUE [1], (Original reason for 3.4.1 release follows)

In the cgnslib code, forward compatibility is always ensured by cg_open function,
which prevents major version incompatibilities and returns gracefully. This well-designed
code provision does not hold for cgnslib v3.4.0, which has the same major version number,
but significantly different NGON data structures. Thus, the library cannot protect the API
users anymore, and unexpected software behaviors might occur.

So, if one upgrades to the new cgnslib 3.4.0, they will create CGNS files
that will crash when read by other parties who are still using the previous v3.x
libraries. This will lead to problems in the community whose aim is to maintain a
general, portable and extensible standard that makes it easier to share files
between sites and collaborators.

RESOLUTION

 Patch 3.4.0 by removing CPEX 41 NGON modification.

 Reintroduce CPEX 41 in the 4.0.0 release.

ACTION

Removed CPEX 41 NGON modification proposal (CGNS-121); these commits were removed:

• Revert "support new ngon layout"
  This reverts commit 83fc242.

• Revert "fix uninitialized memory for offset."
  This reverts commit 3fdc9d8.

• Revert "fix cgnscheck due to new memory layout with ngon_n and nface_n"
  This reverts commit 2c09bad.

[1] 1-28-2020 CGNS Steering Committee Minutes

Fortran:
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Configuration:
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Tools:
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Known Problems

* See https://cgnsorg.atlassian.net