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Problem Report 0709 Details

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Report 0709 Actions

    Problem Report Number 0709
    Submitter's Classification Specification problem
    State Resolved
    Resolution Permanent Interpretation (PIN)
    Problem Resolution ID PIN.X.0102
    Raised 1970-01-01 08:00
    Updated 2003-03-13 08:00
    Published 1995-12-11 08:00
    Product Standard Commands and Utilities V2 (UNIX 95)
    Certification Program The Open Brand certification program
    Test Suite VSC version 4.1.5
    Test Identification POSIX.upe/fc 28
    Specification Commands and Utilities Issue 4 Version 2
    Location in Spec See Problem Text
    Problem Summary PIN4C.00012 This test may fail on implementations because it is ambigious whether or not the fc -l command is included in the command history.
    Problem Text
    This test may fail on implementations because it is ambigious
    whether or not the fc -l command is included in the command history.

    These tests are resolved by the following IEEE POSIX interpretation,
    which permits the behaviour exhibited by our system. The resolution
    below shows that this part of the standard is ambiguous.


    (c) 1995 by the Institute of Electrical and Electronics Engineers Inc.
    All Rights Reserved. Not to be published in full or in part
    without prior written permission from the IEEE.

    _____________________________________________________________________________
    PASC Interpretation reference
    1003.2-92 #136

    _____________________________________________________________________________

    Interpretation Number: XXXX
    Topic: fc -l <first>
    Relevant Sections: 5.12.4

    Interpretation Request:
    -----------------------
    From: andrew@novell.co.uk (Andrew Josey)
    Date: Tue, 15 Aug 1995 16:25:36 +0100


    This is a request for interpretation of IEEE Standard P1003.2


    Historical shells do not implement fc -l <first> as described
    in IEEE Std P1003.2 since they include the current "fc" call in the
    output. Was this change from historical behavior intentional ?

    On page 546, section 5.12.4, lines 2196-2197 specify that "if
    last is omitted, last shall default to the previous command when -l
    is specified". It's clear that "previous command" refers to the
    command immediately preceding the "fc" call from lines 2198-2200,
    as it would make no sense to edit only the fc call.

    Historical Korn Shell behavior with -l when last was not specified
    was to display everying including the current fc command (or whatever command
    caused fc to be invoked). This means that the description
    in the standard is not consistant with historical practice.
    In addition, with historical practice, the 16 commands included
    the current command so that only the 15 previous commands
    are displayed.



    Thank you for your attention in this matter

    Interpretation response
    ------------------------


    The standard is unclear on this issue, and as such no conformance
    distinction can be made between alternative implementations based
    on this. This is being referred to the sponsor.

    There is no clear definition of whether the previous command
    refers to the history before fc was entered or the history
    including the fc command. It also appears that in historic
    practice this definition varied depending on the options given.

    Rationale
    -------------
    None.

    Forwarded to Interpretations group: Aug 15 1995
    Recirculated for 30 day review: Oct 19 1995
    Finalised: Nov 20 1995
    Test Output

    ***********************************************************************
    /tset/POSIX.upe/fc/fc.ex 1 Failed


    Test Information:
    Assertion #28 (C): fc -l <first> defaults <last> to most rec
    <LC> ent command.
    expected last command "fc -l ... 28_1.tmp2 ", got:
    Contents of 28_1.tmp3:
    8 echo ---end---

    ***********************************************************************


    Review Information

    Review Type TSMA Review
    Start Date null
    Completed null
    Status Complete
    Review Recommendation No Resolution Given
    Review Response
    Since POSIX.2 interpretation 1003.2 #136 ruled this issue to be
    ambiguous, a permanent interpretation is recommended.

    Review Type SA Review
    Start Date null
    Completed null
    Status Complete
    Review Resolution Permanent Interpretation (PIN)
    Review Conclusion
    A Permanent Interpretation is granted.

    Problem Reporting System Options:

     

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