PM98022: REWIND OF A GDG WHEN OPENED AS A DATASET (VS DD) CAUSES THE POSITIONING TO RESULT IN THE WRONG PLACE WITHIN THE GDG MEMBERS

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You can track all active APARs for this component.

APAR status

  • Closed as unreproducible in next release.

Error description

  • When a GDG is referenced by its base name in a DD statement,
    z/OS essentially concatenates all of the individual existing
    generations in that GDG under the same DDNAME.  If a program
    issues a rewind at any point while reading such a file, the
    next record to be read will be the first record of the most
    recent generation.  This is how things work for fopen by
    DDNAME.
    
    But when using fopen by DSNAME.... if a program issues
    a rewind while reading such a file, the next
    record to be read is not the first record of the most recent
    generation but rather the first record of the generation in
    which the rewind was issued.
    

Local fix

  • Open GDG using DDNAME vs dataset
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: C/C++ applications that use fopen()          *
    *                 specifying a GDG base name for the dsname    *
    *                 without using a specific generation,         *
    *                 and later using rewind() to reposition       *
    *                 within the implicit concatenation.           *
    ****************************************************************
    * PROBLEM DESCRIPTION: C/C++ applications that use fopen()     *
    *                      specifying a GDG base name for the      *
    *                      dsname without using a specific         *
    *                      generation, and later using rewind()    *
    *                      to reposition within the implicit       *
    *                      concatenation, may not be positioned    *
    *                      to the first record of the most         *
    *                      recent generation.                      *
    ****************************************************************
    * RECOMMENDATION: Change the fopen() to use ddname instead     *
    *                 of dsname.                                   *
    ****************************************************************
    See problem description.
    

Problem conclusion

Temporary fix

Comments

  • This APAR is being closed UR1 with concurrence from the
    submitting customer. This means that a fix to this APAR is
    expected to be delivered from IBM in a release (if any) to be
    available within the next 36 months.
    

APAR Information

  • APAR number

    PM98022

  • Reported component name

    LE C LIBRARY

  • Reported component ID

    568819805

  • Reported release

    780

  • Status

    CLOSED UR1

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-09-27

  • Closed date

    2013-10-10

  • Last modified date

    2013-10-10

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

Fix information

  • Fixed component name

    LE C LIBRARY

  • Fixed component ID

    568819805

Applicable component levels

  • R780 PSN

       UP

  • R790 PSN

       UP



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Document information


More support for:

z/OS XL C/C++
Runtime

Software version:

780

Operating system(s):

MVS, z/OS

Reference #:

PM98022

Modified date:

2013-10-10

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