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Problem Report 0135 Details

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Report 0135 Actions

    Problem Report Number 0135
    Submitter's Classification Test Suite problem
    State Resolved
    Resolution Test Suite Deficiency (TSD)
    Problem Resolution ID TSD.X.0135
    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 3
    Problem Summary TSD4.135 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 to zero and uses
    cfsetospeed to set the output speed to a particular baud rate. It then
    uses tcsetattr to attempt to set that value and calls tcgetattr,
    cfgetispeed, and cfgetospeed to check that both output and input speeds
    were set to the speed passed to cfsetospeed. If either of the values
    returned by cfgetispeed or cfgetospeed does not match, the test judges
    that that baud rate is not supported and tries another. Since tcgetattr
    returns zero for the input speed, the test thinks none of the speeds is
    supported and 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 3 Failed

    Test Description:
    If general terminal interface supported:
    When cfsetispeed(termios_p, 0) and tcsetattr(fildes,
    optional_actions, termios_p) are successfully called, the input
    baud rate shall be set to the output baud rate.
    Posix Ref: Component TCSETATTR Assertion 7.2.1.2-09(C)

    Test Strategy:
    SET IXON in loop back termios structure SET IXOFF in terminal termios
    structure
    For each of the specified baud rates:
    SET input/output baud rate in terminal structure using
    cfsetispeed()/cfsetospeed()
    SET terminal information using tcsetattr()
    OBTAIN terminal information using tcgetattr()
    If input/output baud rate is not set to specified baud rate, baud rate
    is not supported
    SET input/output baud rate in loop back terminal structure using
    cfsetispeed()/cfsetospeed()
    SET terminal information using tcsetattr()
    OBTAIN terminal information using tcgetattr()
    If input/output baud rate is not set to specified baud rate, baud rate
    is not supported
    If baud rate is supported, CREATE [child process|process pair]
    Child: SLEEP using sleep() to allow terminal file to initialise
    SET time out.
    WRITE data to loop back file using write()
    VERIFY that data was written within twice the expected write time
    Parent: READ from terminal file using read()
    VERIFY that all written data can be read
    VERIFY that at least one of the specified baud rates is supported

    Test Information:
    none of specified speeds are supported

    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.

    Problem Reporting System Options:

     

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