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Problem Report 0154 Details

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Report 0154 Actions

    Problem Report Number 0154
    Submitter's Classification Test Suite problem
    State Resolved
    Resolution Test Suite Deficiency (TSD)
    Problem Resolution ID TSD.X.0154
    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/tan 1
    Problem Summary TSD4.154 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 449 for the
    definition of tan(). (The same language is also used for sin() and
    cos()). Under the 'Errors' section these words are used:

    ERRORS
    The tan() function may fail if

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

    [ERANGE] The value to be returned would cause underflows.

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

    The tan() 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 problem was reported via the test error process on February 17, 1994.
    Since then, the test has been changed for VSX4.3.3 alpha release. We would
    like to apply a waiver for VSX4.3.2.

    .FE


    Test Output

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

    Test Description:
    tan(), when called with a large argument, that would cause 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 tan(), when called with a large argument, that would cause
    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: 1.32141
    Bit Representation: expected value: \000\000\000\000\000\000\000\000
    Bit Representation: observed value: \077\365\044\202\107\344\347\253
    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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