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Problem Report 0152 Details

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Report 0152 Actions

    Problem Report Number 0152
    Submitter's Classification Test Suite problem
    State Resolved
    Resolution Test Suite Deficiency (TSD)
    Problem Resolution ID TSD.X.0152
    Raised 1994-06-02 08:00
    Updated 2003-03-13 08:00
    Published 1994-06-08 08:00
    Product Standard Internationalised System Calls and Libraries (XPG4)
    Certification Program The Open Brand certification program
    Test Suite VSX4 version 4.3.2
    Test Identification ANSI.os/maths/cos 2
    Problem Summary TSD4.152 XPG4 no longer permits us to raise the TLOSS exception for sin(), cos() or tan(). This is a change from previous practice, but it is required for conformance. The TLOSS error was part of historic Unix...
    Problem Text
    XPG4 no longer permits us to raise the TLOSS exception for sin(),
    cos() or tan(). This is a change from previous practice, but
    it is required for conformance.

    The TLOSS error was part of historic Unix practice. To see how Unix
    implementations used to handle large arguments, refer to the SVID
    document. Under SVID, an implementation could, at its option, fix
    a maximum allowed argument value and then return TLOSS (Total Loss
    of Significance) if the argument exceeded that value.

    Now comes XPG4 with a different view. Refer to the X/Open CAE
    Specification, System Interfaces and Headers, Issue 4, page 74 for the
    definition of cos(). (The same language is also used for sin() and
    tan()). Under the 'Errors' section these words are used:

    ERRORS
    The cos() function may fail if

    EX [EDOM] The value of x is NaN or x is plus or minus Inf

    [ERANGE] The result underflows

    EX No other errors will occur. <<<<< NOTE THIS LINE!
    ...

    The cos() function may lose accuracy when its argument is far from zero.
    In other words, loss of accuracy for large arguments is expected and
    tolerated by the XPG4 standard. Large, non-infinite arguments are
    considered normal and we must return a value.

    This waiver request was filed earlier as under test error process. The
    test has been changed for VSX4.3.3 alpha release. We would like to
    apply for a waiver for VSX4.3.2.

    .FE


    Test Output

    /tset/ANSI.os/maths/cos/T.cos 2 Failed

    Test Description:
    cos(), when called with a large argument which causes total loss of
    significance, either
    a. returns zero and sets errno to ERANGE;
    b. returns NaN and may set errno to ERANGE.

    Test Strategy:
    CALCULATE floating point constants using mlmachar().
    CREATE child
    REASSIGN stderr to /dev/null to avoid error output from maths
    functions.
    VERIFY cos() when called with an argument which will cause a total
    loss of accuracy, either
    a. returns zero and sets errno to ERANGE;
    b. returns NaN and may set errno to ERANGE.

    Test Information:
    RETURN VALUES: expected: 0, observed: -0.606632
    Bit Representation: expected value: \000\000\000\000\000\000\000\000
    Bit Representation: observed value: \277\343\151\206\260\107\166\074
    ERRNO VALUES: expected: 34 (ERANGE), observed: 0 (NO ERROR)
    ************************************************************************

    Review Information

    Review Type TSMA Review
    Start Date null
    Completed null
    Status Complete
    Review Recommendation No Resolution Given
    Review Response
    This is an accepted test suite deficiency which has already been
    rectified in VSX release 4.3.4. It is recommended that this be
    treated as a test suite deficiency.

    Review Type SA Review
    Start Date null
    Completed null
    Status Complete
    Review Resolution Test Suite Deficiency (TSD)
    Review Conclusion
    This is an agreed test suite deficiency.

    Problem Reporting System Options:

     

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