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ReadKey(3)	      User Contributed Perl Documentation	    ReadKey(3)

NAME
       Term::ReadKey - A perl module for simple	terminal control

SYNOPSIS
	   use Term::ReadKey;
	   ReadMode 4; # Turn off controls keys
	   while (not defined ($key = ReadKey(-1))) {
	       # No key	yet
	   }
	   print "Get key $key\n";
	   ReadMode 0; # Reset tty mode	before exiting

DESCRIPTION
       Term::ReadKey is	a compiled perl	module dedicated to providing simple
       control over terminal driver modes (cbreak, raw,	cooked,	etc.,) support
       for non-blocking	reads, if the architecture allows, and some
       generalized handy functions for working with terminals. One of the main
       goals is	to have	the functions as portable as possible, so you can just
       plug in "use Term::ReadKey" on any architecture and have	a good
       likelihood of it	working.

       Version 2.30.01:	Added handling of arrows, page up/down,	home/end,
       insert/delete keys under	Win32. These keys emit xterm-compatible
       sequences.  Works with Term::ReadLine::Perl.

       ReadMode	MODE [,	Filehandle]
	   Takes an integer argument or	a string synonym (case insensitive),
	   which can currently be one of the following values:

	       INT   SYNONYM	DESCRIPTION

	       0    'restore'	Restore	original settings.

	       1    'normal'	Change to what is commonly the default mode,
				echo on, buffered, signals enabled, Xon/Xoff
				possibly enabled, and 8-bit mode possibly disabled.

	       2    'noecho'	Same as	1, just	with echo off. Nice for
				reading	passwords.

	       3    'cbreak'	Echo off, unbuffered, signals enabled, Xon/Xoff
				possibly enabled, and 8-bit mode possibly enabled.

	       4    'raw'	Echo off, unbuffered, signals disabled,	Xon/Xoff
				disabled, and 8-bit mode possibly disabled.

	       5    'ultra-raw'	Echo off, unbuffered, signals disabled,	Xon/Xoff
				disabled, 8-bit	mode enabled if	parity permits,
				and CR to CR/LF	translation turned off.

	   These functions are automatically applied to	the STDIN handle if no
	   other handle	is supplied. Modes 0 and 5 have	some special
	   properties worth mentioning:	not only will mode 0 restore original
	   settings, but it cause the next ReadMode call to save a new set of
	   default settings. Mode 5 is similar to mode 4, except no CR/LF
	   translation is performed, and if possible, parity will be disabled
	   (only if not	being used by the terminal, however. It	is no
	   different from mode 4 under Windows.)

	   If you just need to read a key at a time, then modes	3 or 4 are
	   probably sufficient.	Mode 4 is a tad	more flexible, but needs a bit
	   more	work to	control. If you	use ReadMode 3,	then you should
	   install a SIGINT or END handler to reset the	terminal (via ReadMode
	   0) if the user aborts the program via "^C". (For any	mode, an END
	   handler consisting of "ReadMode 0" is actually a good idea.)

	   If you are executing	another	program	that may be changing the
	   terminal mode, you will either want to say

	       ReadMode	1;	       # same as ReadMode 'normal'
	       system('someprogram');
	       ReadMode	1;

	   which resets	the settings after the program has run,	or:

	       $somemode=1;
	       ReadMode	0;	       # same as ReadMode 'restore'
	       system('someprogram');
	       ReadMode	1;

	   which records any changes the program may have made,	before
	   resetting the mode.

       ReadKey MODE [, Filehandle]
	   Takes an integer argument, which can	currently be one of the
	   following values:

	       0    Perform a normal read using	getc
	       -1   Perform a non-blocked read
	       >0   Perform a timed read

	   If the filehandle is	not supplied, it will default to STDIN.	If
	   there is nothing waiting in the buffer during a non-blocked read,
	   then	undef will be returned.	 In most situations, you will probably
	   want	to use "ReadKey	-1".

	   NOTE	that if	the OS does not	provide	any known mechanism for	non-
	   blocking reads, then	a "ReadKey -1" can die with a fatal error.
	   This	will hopefully not be common.

	   If MODE is greater then zero, then ReadKey will use it as a timeout
	   value in seconds (fractional	seconds	are allowed), and won't	return
	   "undef" until that time expires.

	   NOTE, again,	that some OS's may not support this timeout behaviour.

	   If MODE is less then	zero, then this	is treated as a	timeout	of
	   zero, and thus will return immediately if no	character is waiting.
	   A MODE of zero, however, will act like a normal getc.

	   NOTE, there are currently some limitations with this	call under
	   Windows.  It	may be possible	that non-blocking reads	will fail when
	   reading repeating keys from more then one console.

       ReadLine	MODE [,	Filehandle]
	   Takes an integer argument, which can	currently be one of the
	   following values:

	       0    Perform a normal read using	scalar(<FileHandle>)
	       -1   Perform a non-blocked read
	       >0   Perform a timed read

	   If there is nothing waiting in the buffer during a non-blocked
	   read, then undef will be returned.

	   NOTE, that if the OS	does not provide any known mechanism for non-
	   blocking reads, then	a "ReadLine 1" can die with a fatal error.
	   This	will hopefully not be common.

	   NOTE	that a non-blocking test is only performed for the first
	   character in	the line, not the entire line.	This call will
	   probably not	do what	you assume, especially with "ReadMode" MODE
	   values higher then 1. For example, pressing Space and then
	   Backspace would appear to leave you where you started, but any
	   timeouts would now be suspended.

	   This	call is	currently not available	under Windows.

       GetTerminalSize [Filehandle]
	   Returns either an empty array if this operation is unsupported, or
	   a four element array	containing: the	width of the terminal in
	   characters, the height of the terminal in character,	the width in
	   pixels, and the height in pixels. (The pixel	size will only be
	   valid in some environments.)

	   NOTE, under Windows,	this function must be called with an output
	   filehandle, such as "STDOUT", or a handle opened to "CONOUT$".

       SetTerminalSize WIDTH,HEIGHT,XPIX,YPIX [, Filehandle]
	   Return -1 on	failure, 0 otherwise.

	   NOTE	that this terminal size	is only	for informative	value, and
	   changing the	size via this mechanism	will not change	the size of
	   the screen. For example, XTerm uses a call like this	when it
	   resizes the screen. If any of the new measurements vary from	the
	   old,	the OS will probably send a SIGWINCH signal to anything
	   reading that	tty or pty.

	   This	call does not work under Windows.

       GetSpeed	[, Filehandle]
	   Returns either an empty array if the	operation is unsupported, or a
	   two value array containing the terminal in and out speeds, in
	   decimal. E.g, an in speed of	9600 baud and an out speed of 4800
	   baud	would be returned as (9600,4800). Note that currently the in
	   and out speeds will always be identical in some OS's.

	   No speeds are reported under	Windows.

       GetControlChars [, Filehandle]
	   Returns an array containing key/value pairs suitable	for a hash.
	   The pairs consist of	a key, the name	of the control
	   character/signal, and the value of that character, as a single
	   character.

	   This	call does nothing under	Windows.

	   Each	key will be an entry from the following	list:

		   DISCARD
		   DSUSPEND
		   EOF
		   EOL
		   EOL2
		   ERASE
		   ERASEWORD
		   INTERRUPT
		   KILL
		   MIN
		   QUIT
		   QUOTENEXT
		   REPRINT
		   START
		   STATUS
		   STOP
		   SUSPEND
		   SWITCH
		   TIME

	   Thus, the following will always return the current interrupt
	   character, regardless of platform.

		   %keys = GetControlChars;
		   $int	= $keys{INTERRUPT};

       SetControlChars [, Filehandle]
	   Takes an array containing key/value pairs, as a hash	will produce.
	   The pairs should consist of a key that is the name of a legal
	   control character/signal, and the value should be either a single
	   character, or a number in the range 0-255. SetControlChars will die
	   with	a runtime error	if an invalid character	name is	passed or
	   there is an error changing the settings. The	list of	valid names is
	   easily available via

		   %cchars = GetControlChars();
		   @cnames = keys %cchars;

	   This	call does nothing under	Windows.

AUTHOR
       Kenneth Albanowski <kjahds@kjahds.com>

       Currently maintained by Jonathan	Stowe <jns@gellyfish.co.uk>

SUPPORT
       The code	is maintained at

	    https://github.com/jonathanstowe/TermReadKey

       Please feel free	to fork	and suggest patches.

LICENSE
       Prior to	the 2.31 release the license statement was:

	Copyright (C) 1994-1999	Kenneth	Albanowski.
		      2001-2005	Jonathan Stowe and others

		      Unlimited	distribution and/or modification is allowed as long as this
		      copyright	notice remains intact.

       And was only stated in the README file.

       Because I believe the original author's intent was to be	more open than
       the other commonly used licenses	I would	like to	leave that in place.
       However if you or your lawyers require something	with some more words
       you can optionally choose to license this under the standard Perl
       license:

	     This module is free software; you can redistribute	it and/or modify it
	     under the terms of	the Artistic License. For details, see the full
	     text of the license in the	file "Artistic"	that should have been provided
	     with the version of perl you are using.

	     This program is distributed in the	hope that it will be useful, but
	     without any warranty; without even	the implied warranty of	merchantability
	     or	fitness	for a particular purpose.

perl v5.32.0			  2020-08-08			    ReadKey(3)

NAME | SYNOPSIS | DESCRIPTION | AUTHOR | SUPPORT | LICENSE

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