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Problem Report 0136 Details

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Report 0136 Actions

    Problem Report Number 0136
    Submitter's Classification Test Suite problem
    State Resolved
    Resolution Test Suite Deficiency (TSD)
    Problem Resolution ID TSD.X.0136
    Raised 1994-05-02 08:00
    Updated 2003-03-13 08:00
    Published 1994-05-04 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 POSIX.os/devclass/cfsetispee 2
    Problem Summary TSD4.136 X/OPEN CAE Specification, System Interfaces and Headers, Issue 4, on tcgetattr, page 457 stated: "If the terminal device does not support split baud rates, the input baud rate stored in the termios st...
    Problem Text

    X/OPEN CAE Specification, System Interfaces and Headers, Issue 4, on
    tcgetattr, page 457 stated:

    "If the terminal device does not support split baud rates, the input baud
    rate stored in the termios structure will be zero."

    POSIX-Part 1: System Application Program Interface (API), IEEE std 1003.1
    first edition 1990-12-07, Section 7.2.1.2, page 143 stated:

    "If differing baud rates are not supported, the rate returned as the
    output baud rate shall be the actual baud rate. The rate returned as the
    input baud rate shall be either the number zero or the output rate ...".

    Our implementation does not support split baud rates. We chose to return
    zero for the input baud rate both to conform to the tcgetattr extension
    in the X/OPEN CAE Specification and to maintain compatibility for
    applications which used the following sequence to change the baud rate:

    * tcgetattr
    * set CBAUD bits in the termios structure's c_cflag by referencing
    them explicitly or by calling cfsetospeed.
    * tcsetattr

    With the POSIX.1-1990 tcsetattr behavior, this would return an error if
    tcgetattr did not return zero for the input baud rate. Under the previous
    version of POSIX.1, it was "implementation-defined" whether tcsetattr would
    return an error when split baud rates are not supported and the input baud
    is non-zero and not equal to the output baud. Our previous releases
    ignored the input baud rate, and used only the output baud rate. This was
    compliant to the older revision of the POSIX.1 specification, and allowed
    the sequence above to work even if the input baud rate returned by
    tcgetattr was non-zero. Returning zero for the input speed allows us to
    implement the POSIX.1-1990 tcsetattr bahavior while not breaking the
    sequence of steps above for setting the baud rate.

    The test uses cfsetispeed to set the input speed in the termios structure
    to zero so that tcsetattr will set the input speed to the same value as
    the output speed. It then attempts to verify the result of the tcsetattr
    by calling tcgetattr and cfgetispeed. It expects the result of cfgetispeed
    to match the output baud rate value. When the test receives zero from
    cfgetispeed, it reports a failure.

    The test should be modified to accept this cfgetispeed behavior, especially
    since this behavior is specified as an extension to the tcgetattr
    description in the X/OPEN CAE Specification.

    Test Output

    /tset/POSIX.os/devclass/cfsetispee/T.cfsetispee 2 Failed

    Test Description:
    If general terminal interface supported:
    For each of the baud rates B50, B75, B110, B134, B150, B200, B300,
    B600, B1200, B1800, B2400, B4800, B9600, B19200 and B38400 a
    successful call to cfsetispeed() followed by a call to tcsetattr()
    shall set the input baud rate to the corresponding speed. At least
    one of these baud rates shall be supported.
    Posix Ref: Component CFSETISPEED Assertion 7.1.2.7.2-05(C)

    Test Strategy:
    SET output baud rate in termios structure using cfsetospeed() to
    correspond with that required for loop back terminal port specified by
    VSX_TERMIOS_SPEED
    SET input baud rate in termios structure to be the same as output baud
    rate using cfsetispeed(termios_p, 0)
    VERIFY that cfsetispeed() returned zero
    SET terminal information from termios structure using tcsetattr()
    VERIFY that tcsetattr() succeeded
    OBTAIN terminal information in termios structure using tcgetattr()
    OBTAIN input baud rate using cfgetispeed() from termios structure
    OBTAIN output baud rate using cfgetospeed() from termios structure
    VERIFY that input and output baud rate are identical

    Test Information:
    tcsetattr() with input speed 0 did not set input speed to same as
    output speed

    Review Information

    Review Type TSMA Review
    Start Date null
    Completed null
    Status Complete
    Review Recommendation No Resolution Given
    Review Response
    This is accepted 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.

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