Term::ReadKey - A perl module for simple terminal control
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
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.
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.
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.
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.
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$.
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.
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};
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.
Kenneth Albanowski <kjahds@kjahds.com>
Currently maintained by Jonathan Stowe <jns@gellyfish.com>