@node Term/ReadKey, Term/ReadLine, Term/Complete, Module List
@unnumbered A perl module for simple terminal control


@unnumberedsec NAME

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

@unnumberedsec 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.

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

@example
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
@end example

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.)

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

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

which resets the settings after the program has run, or:
@end example

@example
$somemode=1;
ReadMode 0;
system(@'someprogram@');
ReadMode 1;

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

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

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

(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 @code{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.

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

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

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 @code{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 @strong{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.

@item 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.

@item SetTerminalSize WIDTH,HEIGHT,XPIX,YPIX [, Filehandle]
Return -1 on failure, 0 otherwise. Note that this terminal size is only for
@strong{informative} value, and changing the size via this mechanism will @strong{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.

@item 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 @strong{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.

@item 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.

Each key will be an entry from the following list:

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

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

@example
%keys = GetControlChars;
$int = $keys@{INTERRUPT@};
@end example

@item 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

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

@end table
