1ReadKey(3)            User Contributed Perl Documentation           ReadKey(3)
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NAME

6       Term::ReadKey - A perl module for simple terminal control
7

SYNOPSIS

9               use Term::ReadKey;
10               ReadMode 4; # Turn off controls keys
11               while (not defined ($key = ReadKey(-1))) {
12                       # No key yet
13               }
14               print "Get key $key\n";
15               ReadMode 0; # Reset tty mode before exiting
16

DESCRIPTION

18       Term::ReadKey is a compiled perl module dedicated to providing simple
19       control over terminal driver modes (cbreak, raw, cooked, etc.,) support
20       for non-blocking reads, if the architecture allows, and some
21       generalized handy functions for working with terminals. One of the main
22       goals is to have the functions as portable as possible, so you can just
23       plug in "use Term::ReadKey" on any architecture and have a good
24       likelyhood of it working.
25
26       ReadMode MODE [, Filehandle]
27               Takes an integer argument, which can currently be one of the
28               following values:
29
30                   0    Restore original settings.
31                   1    Change to cooked mode.
32                   2    Change to cooked mode with echo off.
33                         (Good for passwords)
34                   3    Change to cbreak mode.
35                   4    Change to raw mode.
36                   5    Change to ultra-raw mode.
37                         (LF to CR/LF translation turned off)
38
39                   Or, you may use the synonyms:
40
41                   restore
42                   normal
43                   noecho
44                   cbreak
45                   raw
46                   ultra-raw
47
48               These functions are automatically applied to the STDIN handle
49               if no other handle is supplied. Modes 0 and 5 have some special
50               properties worth mentioning: not only will mode 0 restore
51               original settings, but it cause the next ReadMode call to save
52               a new set of default settings. Mode 5 is similar to mode 4,
53               except no CR/LF translation is performed, and if possible,
54               parity will be disabled (only if not being used by the
55               terminal, however. It is no different from mode 4 under
56               Windows.)
57
58               If you are executing another program that may be changing the
59               terminal mode, you will either want to say
60
61                   ReadMode 1
62                   system('someprogram');
63                   ReadMode 1;
64
65               which resets the settings after the program has run, or:
66
67                   $somemode=1;
68                   ReadMode 0;
69                   system('someprogram');
70                   ReadMode 1;
71
72               which records any changes the program may have made, before
73               resetting the mode.
74
75       ReadKey MODE [, Filehandle]
76               Takes an integer argument, which can currently be one of the
77               following values:
78
79                   0    Perform a normal read using getc
80                   -1   Perform a non-blocked read
81                   >0   Perform a timed read
82
83               (If the filehandle is not supplied, it will default to STDIN.)
84               If there is nothing waiting in the buffer during a non-blocked
85               read, then undef will be returned. Note that if the OS does not
86               provide any known mechanism for non-blocking reads, then a
87               "ReadKey -1" can die with a fatal error. This will hopefully
88               not be common.
89
90               If MODE is greater then zero, then ReadKey will use it as a
91               timeout value in seconds (fractional seconds are allowed), and
92               won't return "undef" until that time expires. (Note, again,
93               that some OS's may not support this timeout behaviour.) If MODE
94               is less then zero, then this is treated as a timeout of zero,
95               and thus will return immediately if no character is waiting. A
96               MODE of zero, however, will act like a normal getc.
97
98               There are currently some limitations with this call under
99               Windows. It may be possible that non-blocking reads will fail
100               when reading repeating keys from more then one console.
101
102       ReadLine MODE [, Filehandle]
103               Takes an integer argument, which can currently be one of the
104               following values:
105
106                   0    Perform a normal read using scalar(<FileHandle>)
107                   -1   Perform a non-blocked read
108                   >0   Perform a timed read
109
110               If there is nothing waiting in the buffer during a non-blocked
111               read, then undef will be returned. Note that if the OS does not
112               provide any known mechanism for non-blocking reads, then a
113               "ReadLine 1" can die with a fatal error. This will hopefully
114               not be common. Note that a non-blocking test is only performed
115               for the first character in the line, not the entire line.  This
116               call will probably not do what you assume, especially with
117               ReadMode's higher then 1. For example, pressing Space and then
118               Backspace would appear to leave you where you started, but any
119               timeouts would now be suspended.
120
121               This call is currently not available under Windows.
122
123       GetTerminalSize [Filehandle]
124               Returns either an empty array if this operation is unsupported,
125               or a four element array containing: the width of the terminal
126               in characters, the height of the terminal in character, the
127               width in pixels, and the height in pixels. (The pixel size will
128               only be valid in some environments.)
129
130               Under Windows, this function must be called with an "output"
131               filehandle, such as STDOUT, or a handle opened to CONOUT$.
132
133       SetTerminalSize WIDTH,HEIGHT,XPIX,YPIX [, Filehandle]
134               Return -1 on failure, 0 otherwise. Note that this terminal size
135               is only for informative value, and changing the size via this
136               mechanism will not change the size of the screen. For example,
137               XTerm uses a call like this when it resizes the screen. If any
138               of the new measurements vary from the old, the OS will probably
139               send a SIGWINCH signal to anything reading that tty or pty.
140
141               This call does not work under Windows.
142
143       GetSpeeds [, Filehandle]
144               Returns either an empty array if the operation is unsupported,
145               or a two value array containing the terminal in and out speeds,
146               in decimal. E.g, an in speed of 9600 baud and an out speed of
147               4800 baud would be returned as (9600,4800). Note that currently
148               the in and out speeds will always be identical in some OS's. No
149               speeds are reported under Windows.
150
151       GetControlChars [, Filehandle]
152               Returns an array containing key/value pairs suitable for a
153               hash. The pairs consist of a key, the name of the control
154               character/signal, and the value of that character, as a single
155               character. This call does nothing under Windows.
156
157               Each key will be an entry from the following list:
158
159                       DISCARD
160                       DSUSPEND
161                       EOF
162                       EOL
163                       EOL2
164                       ERASE
165                       ERASEWORD
166                       INTERRUPT
167                       KILL
168                       MIN
169                       QUIT
170                       QUOTENEXT
171                       REPRINT
172                       START
173                       STATUS
174                       STOP
175                       SUSPEND
176                       SWITCH
177                       TIME
178
179               Thus, the following will always return the current interrupt
180               character, regardless of platform.
181
182                       %keys = GetControlChars;
183                       $int = $keys{INTERRUPT};
184
185       SetControlChars [, Filehandle]
186               Takes an array containing key/value pairs, as a hash will
187               produce. The pairs should consist of a key that is the name of
188               a legal control character/signal, and the value should be
189               either a single character, or a number in the range 0-255.
190               SetControlChars will die with a runtime error if an invalid
191               character name is passed or there is an error changing the
192               settings. The list of valid names is easily available via
193
194                       %cchars = GetControlChars();
195                       @cnames = keys %cchars;
196
197               This call does nothing under Windows.
198

AUTHOR

200       Kenneth Albanowski <kjahds@kjahds.com>
201
202       Currently maintained by Jonathan Stowe <jns@gellyfish.com>
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206perl v5.12.0                      2005-01-11                        ReadKey(3)
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