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CentOS 7.0 - man page for term::readkey (centos section 3)

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 likelyhood of it working.

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

		   0	Restore original settings.
		   1	Change to cooked mode.
		   2	Change to cooked mode with echo off.
			 (Good for passwords)
		   3	Change to cbreak mode.
		   4	Change to raw mode.
		   5	Change to ultra-raw mode.
			 (LF to CR/LF translation turned off)

		   Or, you may use the synonyms:

		   restore
		   normal
		   noecho
		   cbreak
		   raw
		   ultra-raw

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

		   ReadMode 1
		   system('someprogram');
		   ReadMode 1;

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

		   $somemode=1;
		   ReadMode 0;
		   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. 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.

	       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's 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.)

	       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.

       GetSpeeds [, 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.com>

perl v5.16.3				    2005-01-11				       ReadKey(3)


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