128 lines
4.5 KiB
TeX
128 lines
4.5 KiB
TeX
\section{\module{termios} ---
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\POSIX{} style tty control}
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\declaremodule{builtin}{termios}
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\platform{Unix}
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\modulesynopsis{\POSIX\ style tty control.}
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\indexii{\POSIX}{I/O control}
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\indexii{tty}{I/O control}
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This module provides an interface to the \POSIX{} calls for tty I/O
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control. For a complete description of these calls, see the \POSIX{} or
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\UNIX{} manual pages. It is only available for those \UNIX{} versions
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that support \POSIX{} \emph{termios} style tty I/O control (and then
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only if configured at installation time).
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All functions in this module take a file descriptor \var{fd} as their
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first argument. This can be an integer file descriptor, such as
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returned by \code{sys.stdin.fileno()}, or a file object, such as
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\code{sys.stdin} itself.
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This module also defines all the constants needed to work with the
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functions provided here; these have the same name as their
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counterparts in C. Please refer to your system documentation for more
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information on using these terminal control interfaces.
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The module defines the following functions:
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\begin{funcdesc}{tcgetattr}{fd}
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Return a list containing the tty attributes for file descriptor
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\var{fd}, as follows: \code{[}\var{iflag}, \var{oflag}, \var{cflag},
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\var{lflag}, \var{ispeed}, \var{ospeed}, \var{cc}\code{]} where
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\var{cc} is a list of the tty special characters (each a string of
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length 1, except the items with indices \constant{VMIN} and
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\constant{VTIME}, which are integers when these fields are
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defined). The interpretation of the flags and the speeds as well as
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the indexing in the \var{cc} array must be done using the symbolic
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constants defined in the \module{termios}
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module.
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\end{funcdesc}
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\begin{funcdesc}{tcsetattr}{fd, when, attributes}
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Set the tty attributes for file descriptor \var{fd} from the
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\var{attributes}, which is a list like the one returned by
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\function{tcgetattr()}. The \var{when} argument determines when the
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attributes are changed: \constant{TCSANOW} to change immediately,
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\constant{TCSADRAIN} to change after transmitting all queued output,
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or \constant{TCSAFLUSH} to change after transmitting all queued
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output and discarding all queued input.
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\end{funcdesc}
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\begin{funcdesc}{tcsendbreak}{fd, duration}
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Send a break on file descriptor \var{fd}. A zero \var{duration} sends
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a break for 0.25--0.5 seconds; a nonzero \var{duration} has a system
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dependent meaning.
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\end{funcdesc}
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\begin{funcdesc}{tcdrain}{fd}
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Wait until all output written to file descriptor \var{fd} has been
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transmitted.
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\end{funcdesc}
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\begin{funcdesc}{tcflush}{fd, queue}
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Discard queued data on file descriptor \var{fd}. The \var{queue}
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selector specifies which queue: \constant{TCIFLUSH} for the input
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queue, \constant{TCOFLUSH} for the output queue, or
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\constant{TCIOFLUSH} for both queues.
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\end{funcdesc}
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\begin{funcdesc}{tcflow}{fd, action}
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Suspend or resume input or output on file descriptor \var{fd}. The
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\var{action} argument can be \constant{TCOOFF} to suspend output,
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\constant{TCOON} to restart output, \constant{TCIOFF} to suspend
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input, or \constant{TCION} to restart input.
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\end{funcdesc}
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\begin{seealso}
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\seemodule{tty}{Convenience functions for common terminal control
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operations.}
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\end{seealso}
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\subsection{Example}
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\nodename{termios Example}
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Here's a function that prompts for a password with echoing turned
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off. Note the technique using a separate \function{tcgetattr()} call
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and a \keyword{try} ... \keyword{finally} statement to ensure that the
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old tty attributes are restored exactly no matter what happens:
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\begin{verbatim}
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def getpass(prompt = "Password: "):
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import termios, sys
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fd = sys.stdin.fileno()
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old = termios.tcgetattr(fd)
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new = termios.tcgetattr(fd)
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new[3] = new[3] & ~termios.ECHO # lflags
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try:
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termios.tcsetattr(fd, termios.TCSADRAIN, new)
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passwd = raw_input(prompt)
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finally:
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termios.tcsetattr(fd, termios.TCSADRAIN, old)
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return passwd
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\end{verbatim}
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\section{\module{TERMIOS} ---
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Constants used with the \module{termios} module}
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\declaremodule[TERMIOSuppercase]{standard}{TERMIOS}
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\platform{Unix}
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\modulesynopsis{Symbolic constants required to use the
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\module{termios} module.}
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\indexii{\POSIX}{I/O control}
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\indexii{tty}{I/O control}
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\deprecated{2.1}{Import needed constants from \refmodule{termios}
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instead.}
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This module defines the symbolic constants required to use the
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\refmodule{termios}\refbimodindex{termios} module (see the previous
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section). See the \POSIX{} or \UNIX{} manual pages for a list of
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those constants.
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