| \section{\module{termios} --- |
| \POSIX{} style tty control} |
| |
| \declaremodule{builtin}{termios} |
| \platform{Unix} |
| \modulesynopsis{\POSIX{} style tty control.} |
| |
| \indexii{\POSIX{}}{I/O control} |
| \indexii{tty}{I/O control} |
| |
| |
| This module provides an interface to the \POSIX{} calls for tty I/O |
| control. For a complete description of these calls, see the \POSIX{} or |
| \UNIX{} manual pages. It is only available for those \UNIX{} versions |
| that support \POSIX{} \emph{termios} style tty I/O control (and then |
| only if configured at installation time). |
| |
| All functions in this module take a file descriptor \var{fd} as their |
| first argument. This must be an integer file descriptor, such as |
| returned by \code{sys.stdin.fileno()}. |
| |
| This module should be used in conjunction with the |
| \refmodule[TERMIOSuppercase]{TERMIOS}\refstmodindex{TERMIOS} module, |
| which defines the relevant symbolic constants (see the next section). |
| |
| The module defines the following functions: |
| |
| \begin{funcdesc}{tcgetattr}{fd} |
| Return a list containing the tty attributes for file descriptor |
| \var{fd}, as follows: \code{[}\var{iflag}, \var{oflag}, \var{cflag}, |
| \var{lflag}, \var{ispeed}, \var{ospeed}, \var{cc}\code{]} where |
| \var{cc} is a list of the tty special characters (each a string of |
| length 1, except the items with indices \constant{TERMIOS.VMIN} and |
| \constant{TERMIOS.VTIME}, which are integers when these fields are |
| defined). The interpretation of the flags and the speeds as well as |
| the indexing in the \var{cc} array must be done using the symbolic |
| constants defined in the \refmodule[TERMIOSuppercase]{TERMIOS} |
| module. |
| \end{funcdesc} |
| |
| \begin{funcdesc}{tcsetattr}{fd, when, attributes} |
| Set the tty attributes for file descriptor \var{fd} from the |
| \var{attributes}, which is a list like the one returned by |
| \function{tcgetattr()}. The \var{when} argument determines when the |
| attributes are changed: \constant{TERMIOS.TCSANOW} to change |
| immediately, \constant{TERMIOS.TCSADRAIN} to change after transmitting |
| all queued output, or \constant{TERMIOS.TCSAFLUSH} to change after |
| transmitting all queued output and discarding all queued input. |
| \end{funcdesc} |
| |
| \begin{funcdesc}{tcsendbreak}{fd, duration} |
| Send a break on file descriptor \var{fd}. A zero \var{duration} sends |
| a break for 0.25--0.5 seconds; a nonzero \var{duration} has a system |
| dependent meaning. |
| \end{funcdesc} |
| |
| \begin{funcdesc}{tcdrain}{fd} |
| Wait until all output written to file descriptor \var{fd} has been |
| transmitted. |
| \end{funcdesc} |
| |
| \begin{funcdesc}{tcflush}{fd, queue} |
| Discard queued data on file descriptor \var{fd}. The \var{queue} |
| selector specifies which queue: \constant{TERMIOS.TCIFLUSH} for the |
| input queue, \constant{TERMIOS.TCOFLUSH} for the output queue, or |
| \constant{TERMIOS.TCIOFLUSH} for both queues. |
| \end{funcdesc} |
| |
| \begin{funcdesc}{tcflow}{fd, action} |
| Suspend or resume input or output on file descriptor \var{fd}. The |
| \var{action} argument can be \constant{TERMIOS.TCOOFF} to suspend |
| output, \constant{TERMIOS.TCOON} to restart output, |
| \constant{TERMIOS.TCIOFF} to suspend input, or |
| \constant{TERMIOS.TCION} to restart input. |
| \end{funcdesc} |
| |
| \subsection{Example} |
| \nodename{termios Example} |
| |
| Here's a function that prompts for a password with echoing turned |
| off. Note the technique using a separate \function{tcgetattr()} call |
| and a \keyword{try} ... \keyword{finally} statement to ensure that the |
| old tty attributes are restored exactly no matter what happens: |
| |
| \begin{verbatim} |
| def getpass(prompt = "Password: "): |
| import termios, TERMIOS, sys |
| fd = sys.stdin.fileno() |
| old = termios.tcgetattr(fd) |
| new = termios.tcgetattr(fd) |
| new[3] = new[3] & ~TERMIOS.ECHO # lflags |
| try: |
| termios.tcsetattr(fd, TERMIOS.TCSADRAIN, new) |
| passwd = raw_input(prompt) |
| finally: |
| termios.tcsetattr(fd, TERMIOS.TCSADRAIN, old) |
| return passwd |
| \end{verbatim} |
| |
| |
| \section{\module{TERMIOS} --- |
| Constants used with the \module{termios} module} |
| |
| \declaremodule[TERMIOSuppercase]{standard}{TERMIOS} |
| \platform{Unix} |
| \modulesynopsis{Symbolic constants required to use the |
| \module{termios} module.} |
| |
| |
| \indexii{\POSIX{}}{I/O control} |
| \indexii{tty}{I/O control} |
| |
| This module defines the symbolic constants required to use the |
| \refmodule{termios}\refbimodindex{termios} module (see the previous |
| section). See the \POSIX{} or \UNIX{} manual pages (or the source) |
| for a list of those constants. |
| |
| Note: this module resides in a system-dependent subdirectory of the |
| Python library directory. You may have to generate it for your |
| particular system using the script \file{Tools/scripts/h2py.py}. |