cfsetospeed(3)                                           cfsetospeed(3)

  tcsetattr()

  NAME

    cfgetispeed(), cfsetispeed(), cfgetospeed(), cfsetospeed(), tcgetattr(),
    tcsetattr() - manipulate the termios structure

  SYNOPSIS

    #include 

    speed_t cfgetispeed (const struct termios *t)
    int cfsetispeed (struct termios *t, speed_t speed)
    speed_t cfgetospeed (const struct termios *t)
    int cfsetospeed (struct termios *t, speed_t speed)
    int tcgetattr (int fd, struct termios *t)
    int tcsetattr (int fd, int action, const struct termios *t)

  DESCRIPTION

    The tcgetattr(2) and tcsetattr(2) functions are provided for getting and
    setting the termios structure.

    The cfgetispeed(3), cfsetispeed(3), cfgetospeed(3) and cfsetospeed(3)
    functions are provided for getting and setting the baud rate values in the
    termios structure. These functions set attributes for the terminal, but
    those attributes do not take effect, nor are all errors detected, until
    the tcsetattr(2) function is called. Certain values for baud rates set in
    the termios structure and passed to tcsetattr(2) have special meanings.
    These are discussed in the portion of the manual page that describes the
    tcsetattr(2) function.

  GETTING AND SETTING THE BAUD RATE

    The input and output baud rates are found in the termios structure. The
    unsigned integer speed_t is typedef'd in the include file . Use
    the symbolic values defined there, since the value of the integer does not
    necessarily correspond to the baud rate being represented. (For example,
    B9600 may not be 9600.)
    Name     Description     Name       Description

    B0       Hang up         B600       600 baud

    B50      50 baud         B1200      1200 baud

    B75      75 baud         B1800      1800 baud

    B110     110 baud        B2400      2400 baud

    B134     134.5 baud      B4800      4800 baud

    B150     150 baud        B9600      9600 baud

    B200     200 baud        B19200     19,200 baud

    B300     300 baud        B38400     38,400 baud

    The cfgetispeed(3) function returns the input baud rate in the termios
    structure referenced by tp.

    The cfsetispeed(3) function sets the input baud rate in the termios
    structure referenced by tp to speed.

    The cfgetospeed(3) function returns the output baud rate in the termios
    structure referenced by tp.

    The cfsetospeed(3) function sets the output baud rate in the termios
    structure referenced by tp to speed.

    Upon successful completion, the functions cfsetispeed(3) and
    cfsetospeed(3) return a value of 0. Otherwise, a value of -1 is returned
    and the global variable errno is set to indicate the error.

  GETTING AND SETTING THE TERMIOS STATE

    This section describes the functions that are used to control the general
    terminal interface. Unless otherwise noted for a specific command, these
    functions are restricted from use by background processes. Attempts to
    perform these operations shall cause the process group to be sent a
    SIGTTOU signal. If the calling process is blocking or ignoring SIGTTOU
    signals, the process is allowed to perform the operation and the SIGTTOU
    signal is not sent.

    In all the functions, although fd is an open file descriptor, the
    functions affect the underlying terminal file, not just the open file
    description associated with the particular file descriptor.

    The tcgetattr(2) function copies the parameters associated with the
    terminal referenced by fd in the termios structure referenced by tp. This
    function is allowed from a background process, however, the terminal
    attributes may be subsequently changed by a foreground process.

    The tcsetattr(2) function sets the parameters associated with the terminal
    from the termios structure referenced by tp. The action field is created
    by ORing the following values, as specified in the include file
    .

    TCSANOW
        The change occurs immediately.

    TCSADRAIN
        The change occurs after all output written to fd has been transmitted
        to the terminal. This value of action should be used when changing
        parameters that affect output.

    TCSAFLUSH
        The change occurs after all output written to fd has been transmitted
        to the terminal. Additionally, any input that has been received but
        not read is discarded.

    The 0 baud rate is used to terminate the connection. If 0 is specified as
    the output speed to the function tcsetattr(2), modem control will no
    longer be asserted on the terminal, disconnecting the terminal.

    If zero is specified as the input speed to the function tcsetattr(2), the
    input baud rate will be set to the same value as that specified by the
    output baud rate.

  RETURN VALUES

    If tcsetattr(2) is unable to make any of the requested changes, it returns
    -1 and sets errno. Otherwise, it makes all of the requested changes it
    can. If the specified input and output baud rates differ and are a
    combination that is not supported, neither baud rate is changed.

    Upon successful completion, the functions tcgetattr(2) and tcsetattr(2)
    return a value of 0. Otherwise, they return -1 and the global variable
    errno is set to indicate the error.

  ERRORS

    The functions tcgetattr(2) and tcsetattr(2) can set errno to the following
    values:

    [EBADF]
        The fd argument to tcgetattr(2) or tcsetattr(2) was not a valid file
        descriptor.

    [EINTR]
        The tcsetattr(2) function was interrupted by a signal.

    [EINVAL]
        The action argument to the tcsetattr(2) function was not valid, or an
        attempt was made to change an attribute represented in the termios
        structure to an unsupported value.

    [ENOTTY]
        The file associated with the fd argument to tcgetattr(2) or
        tcsetattr(2) is not a terminal.

  NOTES

    As of this writing, setting (or getting) the baud rate for a console
    window is unimportant, since on single PCs there is no modulated phone
    line connecting the terminal and the subsystem.

  SEE ALSO

    tcsendbreak(2)

    termios(4)

  USAGE NOTES

    All of these functions are thread safe.

    All of these functions are async-signal safe.