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gh-85984: New additions and improvements to the tty library. (#101832)
New additions to the tty library. Functions added: cfmakeraw(), and cfmakecbreak(). The functions setcbreak() and setraw() now return original termios to save an extra tcgetattr() call. --------- Signed-off-by: Soumendra Ganguly <soumendraganguly@gmail.com> Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com> Co-authored-by: Gregory P. Smith [Google LLC] <greg@krypto.org>
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‎Doc/library/tty.rst

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@@ -20,18 +20,36 @@ Because it requires the :mod:`termios` module, it will work only on Unix.
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The :mod:`tty` module defines the following functions:
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.. function:: cfmakeraw(mode)
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Convert the tty attribute list *mode*, which is a list like the one returned
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by :func:`termios.tcgetattr`, to that of a tty in raw mode.
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.. versionadded:: 3.12
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.. function:: cfmakecbreak(mode)
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Convert the tty attribute list *mode*, which is a list like the one returned
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by :func:`termios.tcgetattr`, to that of a tty in cbreak mode.
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.. versionadded:: 3.12
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.. function:: setraw(fd, when=termios.TCSAFLUSH)
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Change the mode of the file descriptor *fd* to raw. If *when* is omitted, it
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defaults to :const:`termios.TCSAFLUSH`, and is passed to
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:func:`termios.tcsetattr`.
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:func:`termios.tcsetattr`. The return value of :func:`termios.tcgetattr`
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is saved before setting *fd* to raw mode; this value is returned.
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.. function:: setcbreak(fd, when=termios.TCSAFLUSH)
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Change the mode of file descriptor *fd* to cbreak. If *when* is omitted, it
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defaults to :const:`termios.TCSAFLUSH`, and is passed to
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:func:`termios.tcsetattr`.
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:func:`termios.tcsetattr`. The return value of :func:`termios.tcgetattr`
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is saved before setting *fd* to cbreak mode; this value is returned.
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.. seealso::

‎Lib/tty.py

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from termios import *
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__all__ = ["setraw", "setcbreak"]
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__all__ = ["cfmakeraw", "cfmakecbreak", "setraw", "setcbreak"]
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# Indexes for termios list.
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# Indices for termios list.
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IFLAG = 0
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OFLAG = 1
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CFLAG = 2
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OSPEED = 5
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CC = 6
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def setraw(fd, when=TCSAFLUSH):
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"""Put terminal into a raw mode."""
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mode = tcgetattr(fd)
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mode[IFLAG] = mode[IFLAG] & ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON)
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mode[OFLAG] = mode[OFLAG] & ~(OPOST)
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mode[CFLAG] = mode[CFLAG] & ~(CSIZE | PARENB)
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mode[CFLAG] = mode[CFLAG] | CS8
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mode[LFLAG] = mode[LFLAG] & ~(ECHO | ICANON | IEXTEN | ISIG)
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def cfmakeraw(mode):
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"""Make termios mode raw."""
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# Clear all POSIX.1-2017 input mode flags.
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# See chapter 11 "General Terminal Interface"
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# of POSIX.1-2017 Base Definitions.
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mode[IFLAG] &= ~(IGNBRK | BRKINT | IGNPAR | PARMRK | INPCK | ISTRIP |
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INLCR | IGNCR | ICRNL | IXON | IXANY | IXOFF)
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# Do not post-process output.
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mode[OFLAG] &= ~OPOST
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# Disable parity generation and detection; clear character size mask;
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# let character size be 8 bits.
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mode[CFLAG] &= ~(PARENB | CSIZE)
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mode[CFLAG] |= CS8
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# Clear all POSIX.1-2017 local mode flags.
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mode[LFLAG] &= ~(ECHO | ECHOE | ECHOK | ECHONL | ICANON |
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IEXTEN | ISIG | NOFLSH | TOSTOP)
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# POSIX.1-2017, 11.1.7 Non-Canonical Mode Input Processing,
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# Case B: MIN>0, TIME=0
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# A pending read shall block until MIN (here 1) bytes are received,
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# or a signal is received.
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mode[CC][VMIN] = 1
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mode[CC][VTIME] = 0
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tcsetattr(fd, when, mode)
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def setcbreak(fd, when=TCSAFLUSH):
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"""Put terminal into a cbreak mode."""
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mode = tcgetattr(fd)
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mode[LFLAG] = mode[LFLAG] & ~(ECHO | ICANON)
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def cfmakecbreak(mode):
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"""Make termios mode cbreak."""
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# Do not map CR to NL on input.
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mode[IFLAG] &= ~(ICRNL)
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# Do not echo characters; disable canonical input.
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mode[LFLAG] &= ~(ECHO | ICANON)
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# POSIX.1-2017, 11.1.7 Non-Canonical Mode Input Processing,
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# Case B: MIN>0, TIME=0
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# A pending read shall block until MIN (here 1) bytes are received,
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# or a signal is received.
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mode[CC][VMIN] = 1
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mode[CC][VTIME] = 0
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tcsetattr(fd, when, mode)
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def setraw(fd, when=TCSAFLUSH):
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"""Put terminal into raw mode."""
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mode = tcgetattr(fd)
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new = list(mode)
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cfmakeraw(new)
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tcsetattr(fd, when, new)
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return mode
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def setcbreak(fd, when=TCSAFLUSH):
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"""Put terminal into cbreak mode."""
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mode = tcgetattr(fd)
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new = list(mode)
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cfmakecbreak(new)
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tcsetattr(fd, when, new)
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return mode

‎Misc/NEWS.d/next/Library/2023-02-11-21-18-10.gh-issue-85984.nvzOD0.rst

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Add :func:`tty.cfmakeraw` and :func:`tty.cfmakecbreak` to :mod:`tty` and
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modernize, the behavior of :func:`tty.setraw` and :func:`tty.setcbreak` to use
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POSIX.1-2017 Chapter 11 "General Terminal Interface" flag masks by default.

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