416 lines
14 KiB
Plaintext
416 lines
14 KiB
Plaintext
'\" t
|
|
.\"***************************************************************************
|
|
.\" Copyright (c) 1998-2018,2019 Free Software Foundation, Inc. *
|
|
.\" *
|
|
.\" Permission is hereby granted, free of charge, to any person obtaining a *
|
|
.\" copy of this software and associated documentation files (the *
|
|
.\" "Software"), to deal in the Software without restriction, including *
|
|
.\" without limitation the rights to use, copy, modify, merge, publish, *
|
|
.\" distribute, distribute with modifications, sublicense, and/or sell *
|
|
.\" copies of the Software, and to permit persons to whom the Software is *
|
|
.\" furnished to do so, subject to the following conditions: *
|
|
.\" *
|
|
.\" The above copyright notice and this permission notice shall be included *
|
|
.\" in all copies or substantial portions of the Software. *
|
|
.\" *
|
|
.\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
|
|
.\" OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF *
|
|
.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. *
|
|
.\" IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, *
|
|
.\" DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR *
|
|
.\" OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR *
|
|
.\" THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
|
|
.\" *
|
|
.\" Except as contained in this notice, the name(s) of the above copyright *
|
|
.\" holders shall not be used in advertising or otherwise to promote the *
|
|
.\" sale, use or other dealings in this Software without prior written *
|
|
.\" authorization. *
|
|
.\"***************************************************************************
|
|
.\"
|
|
.\" $Id: curs_getch.3x,v 1.54 2019/11/30 21:06:30 tom Exp $
|
|
.TH curs_getch 3X ""
|
|
.na
|
|
.hy 0
|
|
.ie \n(.g .ds `` \(lq
|
|
.el .ds `` ``
|
|
.ie \n(.g .ds '' \(rq
|
|
.el .ds '' ''
|
|
.de bP
|
|
.ie n .IP \(bu 4
|
|
.el .IP \(bu 2
|
|
..
|
|
.SH NAME
|
|
\fBgetch\fR,
|
|
\fBwgetch\fR,
|
|
\fBmvgetch\fR,
|
|
\fBmvwgetch\fR,
|
|
\fBungetch\fR,
|
|
\fBhas_key\fR \- get (or push back) characters from \fBcurses\fR terminal keyboard
|
|
.ad
|
|
.hy
|
|
.SH SYNOPSIS
|
|
\fB#include <curses.h>\fR
|
|
.PP
|
|
\fBint getch(void);\fR
|
|
.br
|
|
\fBint wgetch(WINDOW *\fP\fIwin);\fR
|
|
.br
|
|
\fBint mvgetch(int \fP\fIy\fP\fB, int \fP\fIx\fP\fB);\fR
|
|
.br
|
|
\fBint mvwgetch(WINDOW *\fP\fIwin\fP\fB, int \fP\fIy\fP\fB, int \fP\fIx\fP\fB);\fR
|
|
.br
|
|
\fBint ungetch(int \fP\fIch\fP\fB);\fR
|
|
.br
|
|
\fBint has_key(int \fP\fIch\fP\fB);\fR
|
|
.br
|
|
.SH DESCRIPTION
|
|
.SS Reading characters
|
|
The \fBgetch\fR, \fBwgetch\fR, \fBmvgetch\fR and \fBmvwgetch\fR, routines read
|
|
a character from the window.
|
|
In no-delay mode, if no input is waiting, the value \fBERR\fR is returned.
|
|
In delay mode, the program waits until the system
|
|
passes text through to the program.
|
|
Depending on the setting of \fBcbreak\fR,
|
|
this is after one character (cbreak mode),
|
|
or after the first newline (nocbreak mode).
|
|
In half-delay mode,
|
|
the program waits until a character is typed or the
|
|
specified timeout has been reached.
|
|
.PP
|
|
If \fBecho\fR is enabled, and the window is not a pad,
|
|
then the character will also be echoed into the
|
|
designated window according to the following rules:
|
|
.bP
|
|
If the character is the current erase character, left arrow, or backspace,
|
|
the cursor is moved one space to the left and that screen position is erased
|
|
as if \fBdelch\fR had been called.
|
|
.bP
|
|
If the character value is any other \fBKEY_\fR define, the user is alerted
|
|
with a \fBbeep\fR call.
|
|
.bP
|
|
If the character is a carriage-return,
|
|
and if \fBnl\fP is enabled,
|
|
it is translated to a line-feed after echoing.
|
|
.bP
|
|
Otherwise the character is simply output to the screen.
|
|
.PP
|
|
If the window is not a pad, and it has been moved or modified since the last
|
|
call to \fBwrefresh\fR, \fBwrefresh\fR will be called before another character
|
|
is read.
|
|
.SS Keypad mode
|
|
.PP
|
|
If \fBkeypad\fR is \fBTRUE\fR, and a function key is pressed, the token for
|
|
that function key is returned instead of the raw characters:
|
|
.bP
|
|
The predefined function
|
|
keys are listed in \fB<curses.h>\fR as macros with values outside the range
|
|
of 8-bit characters.
|
|
Their names begin with \fBKEY_\fR.
|
|
.bP
|
|
Other (user-defined) function keys which may be defined
|
|
using \fBdefine_key\fP(3X)
|
|
have no names, but also are expected to have values outside the range of
|
|
8-bit characters.
|
|
.PP
|
|
Thus, a variable
|
|
intended to hold the return value of a function key must be of short size or
|
|
larger.
|
|
.PP
|
|
When a character that could be the beginning of a function key is received
|
|
(which, on modern terminals, means an escape character),
|
|
\fBcurses\fR sets a timer.
|
|
If the remainder of the sequence does not come in within the designated
|
|
time, the character is passed through;
|
|
otherwise, the function key value is returned.
|
|
For this reason, many terminals experience a delay between the time
|
|
a user presses the escape key and the escape is returned to the program.
|
|
.PP
|
|
In \fBncurses\fP, the timer normally expires after
|
|
the value in \fBESCDELAY\fP (see \fBcurs_variables\fP(3X)).
|
|
If \fBnotimeout\fP is \fBTRUE\fP, the timer does not expire;
|
|
it is an infinite (or very large) value.
|
|
Because function keys usually begin with an escape character,
|
|
the terminal may appear to hang in notimeout mode after pressing the escape key
|
|
until another key is pressed.
|
|
.SS Ungetting characters
|
|
.PP
|
|
The \fBungetch\fR routine places \fIch\fR back onto the input queue to be
|
|
returned by the next call to \fBwgetch\fR.
|
|
There is just one input queue for all windows.
|
|
.PP
|
|
.SS Predefined key-codes
|
|
The following special keys are defined in \fB<curses.h>\fR.
|
|
.bP
|
|
Except for the special case \fBKEY_RESIZE\fP,
|
|
it is necessary to enable \fBkeypad\fR for \fBgetch\fP to return these codes.
|
|
.bP
|
|
Not all of these are necessarily supported on any particular terminal.
|
|
.bP
|
|
The naming convention may seem obscure, with some apparent
|
|
misspellings (such as \*(``RSUME\*('' for \*(``resume\*('').
|
|
The names correspond to the long terminfo capability names for the keys,
|
|
and were defined long ago, in the 1980s.
|
|
.PP
|
|
.TS
|
|
center tab(/) ;
|
|
l l .
|
|
\fIName\fR/\fIKey\fR \fIname\fR
|
|
_
|
|
KEY_BREAK/Break key
|
|
KEY_DOWN/The four arrow keys ...
|
|
KEY_UP
|
|
KEY_LEFT
|
|
KEY_RIGHT
|
|
KEY_HOME/Home key (upward+left arrow)
|
|
KEY_BACKSPACE/Backspace
|
|
KEY_F0/T{
|
|
Function keys; space for 64 keys is reserved.
|
|
T}
|
|
KEY_F(\fIn\fR)/T{
|
|
For 0 \(<= \fIn\fR \(<= 63
|
|
T}
|
|
KEY_DL/Delete line
|
|
KEY_IL/Insert line
|
|
KEY_DC/Delete character
|
|
KEY_IC/Insert char or enter insert mode
|
|
KEY_EIC/Exit insert char mode
|
|
KEY_CLEAR/Clear screen
|
|
KEY_EOS/Clear to end of screen
|
|
KEY_EOL/Clear to end of line
|
|
KEY_SF/Scroll 1 line forward
|
|
KEY_SR/Scroll 1 line backward (reverse)
|
|
KEY_NPAGE/Next page
|
|
KEY_PPAGE/Previous page
|
|
KEY_STAB/Set tab
|
|
KEY_CTAB/Clear tab
|
|
KEY_CATAB/Clear all tabs
|
|
KEY_ENTER/Enter or send
|
|
KEY_SRESET/Soft (partial) reset
|
|
KEY_RESET/Reset or hard reset
|
|
KEY_PRINT/Print or copy
|
|
KEY_LL/Home down or bottom (lower left)
|
|
KEY_A1/Upper left of keypad
|
|
KEY_A3/Upper right of keypad
|
|
KEY_B2/Center of keypad
|
|
KEY_C1/Lower left of keypad
|
|
KEY_C3/Lower right of keypad
|
|
KEY_BTAB/Back tab key
|
|
KEY_BEG/Beg(inning) key
|
|
KEY_CANCEL/Cancel key
|
|
KEY_CLOSE/Close key
|
|
KEY_COMMAND/Cmd (command) key
|
|
KEY_COPY/Copy key
|
|
KEY_CREATE/Create key
|
|
KEY_END/End key
|
|
KEY_EXIT/Exit key
|
|
KEY_FIND/Find key
|
|
KEY_HELP/Help key
|
|
KEY_MARK/Mark key
|
|
KEY_MESSAGE/Message key
|
|
KEY_MOUSE/Mouse event read
|
|
KEY_MOVE/Move key
|
|
KEY_NEXT/Next object key
|
|
KEY_OPEN/Open key
|
|
KEY_OPTIONS/Options key
|
|
KEY_PREVIOUS/Previous object key
|
|
KEY_REDO/Redo key
|
|
KEY_REFERENCE/Ref(erence) key
|
|
KEY_REFRESH/Refresh key
|
|
KEY_REPLACE/Replace key
|
|
KEY_RESIZE/Screen resized
|
|
KEY_RESTART/Restart key
|
|
KEY_RESUME/Resume key
|
|
KEY_SAVE/Save key
|
|
KEY_SBEG/Shifted beginning key
|
|
KEY_SCANCEL/Shifted cancel key
|
|
KEY_SCOMMAND/Shifted command key
|
|
KEY_SCOPY/Shifted copy key
|
|
KEY_SCREATE/Shifted create key
|
|
KEY_SDC/Shifted delete char key
|
|
KEY_SDL/Shifted delete line key
|
|
KEY_SELECT/Select key
|
|
KEY_SEND/Shifted end key
|
|
KEY_SEOL/Shifted clear line key
|
|
KEY_SEXIT/Shifted exit key
|
|
KEY_SFIND/Shifted find key
|
|
KEY_SHELP/Shifted help key
|
|
KEY_SHOME/Shifted home key
|
|
KEY_SIC/Shifted input key
|
|
KEY_SLEFT/Shifted left arrow key
|
|
KEY_SMESSAGE/Shifted message key
|
|
KEY_SMOVE/Shifted move key
|
|
KEY_SNEXT/Shifted next key
|
|
KEY_SOPTIONS/Shifted options key
|
|
KEY_SPREVIOUS/Shifted prev key
|
|
KEY_SPRINT/Shifted print key
|
|
KEY_SREDO/Shifted redo key
|
|
KEY_SREPLACE/Shifted replace key
|
|
KEY_SRIGHT/Shifted right arrow
|
|
KEY_SRSUME/Shifted resume key
|
|
KEY_SSAVE/Shifted save key
|
|
KEY_SSUSPEND/Shifted suspend key
|
|
KEY_SUNDO/Shifted undo key
|
|
KEY_SUSPEND/Suspend key
|
|
KEY_UNDO/Undo key
|
|
.TE
|
|
.PP
|
|
Keypad is arranged like this:
|
|
.br
|
|
.TS
|
|
center allbox tab(/) ;
|
|
c c c .
|
|
\fBA1\fR/\fBup\fR/\fBA3\fR
|
|
\fBleft\fR/\fBB2\fR/\fBright\fR
|
|
\fBC1\fR/\fBdown\fR/\fBC3\fR
|
|
.TE
|
|
.sp
|
|
A few of these predefined values do \fInot\fP correspond to a real key:
|
|
.bP
|
|
.B KEY_RESIZE
|
|
is returned when the \fBSIGWINCH\fP signal has been detected
|
|
(see \fBinitscr\fP(3X) and \fBresizeterm\fR(3X)).
|
|
This code is returned whether or not \fBkeypad\fP has been enabled.
|
|
.bP
|
|
.B KEY_MOUSE
|
|
is returned for mouse-events (see \fBcurs_mouse\fR(3X)).
|
|
This code relies upon whether or not \fBkeypad\fP(3X) has been enabled,
|
|
because (e.g., with \fIxterm\fP mouse prototocol) ncurses must
|
|
read escape sequences,
|
|
just like a function key.
|
|
.SS Testing key-codes
|
|
.PP
|
|
The \fBhas_key\fR routine takes a key-code value from the above list, and
|
|
returns \fBTRUE\fP or \fBFALSE\fP according to whether
|
|
the current terminal type recognizes a key with that value.
|
|
.PP
|
|
The library also supports these extensions:
|
|
.RS 3
|
|
.TP 5
|
|
.B define_key
|
|
defines a key-code for a given string (see \fBdefine_key\fP(3X)).
|
|
.TP 5
|
|
.B key_defined
|
|
checks if there is a key-code defined for a given
|
|
string (see \fBkey_defined\fP(3X)).
|
|
.RE
|
|
.PP
|
|
.SH RETURN VALUE
|
|
All routines return the integer \fBERR\fR upon failure and an integer value
|
|
other than \fBERR\fR (\fBOK\fR in the case of \fBungetch\fP) upon successful
|
|
completion.
|
|
.RS 3
|
|
.TP 5
|
|
\fBungetch\fP
|
|
returns \fBERR\fP
|
|
if there is no more room in the FIFO.
|
|
.TP
|
|
\fBwgetch\fP
|
|
returns \fBERR\fP
|
|
if the window pointer is null, or
|
|
if its timeout expires without having any data, or
|
|
if the execution was interrupted by a signal (\fBerrno\fR will be set to
|
|
\fBEINTR\fR).
|
|
.RE
|
|
.PP
|
|
Functions with a \*(``mv\*('' prefix first perform a cursor movement using
|
|
\fBwmove\fP, and return an error if the position is outside the window,
|
|
or if the window pointer is null.
|
|
.SH NOTES
|
|
Use of the escape key by a programmer for a single character function is
|
|
discouraged, as it will cause a delay of up to one second while the
|
|
keypad code looks for a following function-key sequence.
|
|
.PP
|
|
Some keys may be the same as commonly used control
|
|
keys, e.g.,
|
|
\fBKEY_ENTER\fP versus control/M,
|
|
\fBKEY_BACKSPACE\fP versus control/H.
|
|
Some curses implementations may differ according to whether they
|
|
treat these control keys specially (and ignore the terminfo), or
|
|
use the terminfo definitions.
|
|
\fBNcurses\fR uses the terminfo definition.
|
|
If it says that \fBKEY_ENTER\fP is control/M,
|
|
\fBgetch\fR will return \fBKEY_ENTER\fP
|
|
when you press control/M.
|
|
.PP
|
|
Generally, \fBKEY_ENTER\fP denotes the character(s) sent by the \fIEnter\fP
|
|
key on the numeric keypad:
|
|
.bP
|
|
the terminal description lists the most useful keys,
|
|
.bP
|
|
the \fIEnter\fP key on the regular keyboard is already handled by
|
|
the standard ASCII characters for carriage-return and line-feed,
|
|
.bP
|
|
depending on whether \fBnl\fP or \fBnonl\fP was called,
|
|
pressing \*(``Enter\*('' on the regular keyboard
|
|
may return either a carriage-return or line-feed, and finally
|
|
.bP
|
|
\*(``Enter or send\*('' is the standard description for this key.
|
|
.PP
|
|
When using \fBgetch\fR, \fBwgetch\fR, \fBmvgetch\fR, or
|
|
\fBmvwgetch\fR, nocbreak mode (\fBnocbreak\fR) and echo mode
|
|
(\fBecho\fR) should not be used at the same time.
|
|
Depending on the
|
|
state of the tty driver when each character is typed, the program may
|
|
produce undesirable results.
|
|
.PP
|
|
Note that \fBgetch\fR, \fBmvgetch\fR, and \fBmvwgetch\fR may be macros.
|
|
.PP
|
|
Historically, the set of keypad macros was largely defined by the extremely
|
|
function-key-rich keyboard of the AT&T 7300, aka 3B1, aka Safari 4.
|
|
Modern
|
|
personal computers usually have only a small subset of these.
|
|
IBM PC-style
|
|
consoles typically support little more than \fBKEY_UP\fR, \fBKEY_DOWN\fR,
|
|
\fBKEY_LEFT\fR, \fBKEY_RIGHT\fR, \fBKEY_HOME\fR, \fBKEY_END\fR,
|
|
\fBKEY_NPAGE\fR, \fBKEY_PPAGE\fR, and function keys 1 through 12.
|
|
The Ins key
|
|
is usually mapped to \fBKEY_IC\fR.
|
|
.SH PORTABILITY
|
|
The *get* functions are described in the XSI Curses standard, Issue 4.
|
|
They
|
|
read single-byte characters only.
|
|
The standard specifies that they return
|
|
\fBERR\fR on failure, but specifies no error conditions.
|
|
.PP
|
|
The echo behavior of these functions on input of \fBKEY_\fR or backspace
|
|
characters was not specified in the SVr4 documentation.
|
|
This description is
|
|
adopted from the XSI Curses standard.
|
|
.PP
|
|
The behavior of \fBgetch\fR and friends in the presence of handled signals is
|
|
unspecified in the SVr4 and XSI Curses documentation.
|
|
Under historical curses
|
|
implementations, it varied depending on whether the operating system's
|
|
implementation of handled signal receipt interrupts a \fBread\fR(2) call in
|
|
progress or not, and also (in some implementations) depending on whether an
|
|
input timeout or non-blocking mode has been set.
|
|
.PP
|
|
\fBKEY_MOUSE\fP is mentioned in XSI Curses, along with a few related
|
|
terminfo capabilities, but no higher-level functions use the feature.
|
|
The implementation in ncurses is an extension.
|
|
.PP
|
|
\fBKEY_RESIZE\fP is an extension first implemented for ncurses.
|
|
NetBSD curses later added this extension.
|
|
.PP
|
|
Programmers concerned about portability should be prepared for either of two
|
|
cases: (a) signal receipt does not interrupt \fBgetch\fR; (b) signal receipt
|
|
interrupts \fBgetch\fR and causes it to return \fBERR\fP with \fBerrno\fR set to
|
|
\fBEINTR\fR.
|
|
.PP
|
|
The \fBhas_key\fR function is unique to \fBncurses\fR.
|
|
We recommend that
|
|
any code using it be conditionalized on the \fBNCURSES_VERSION\fR feature macro.
|
|
.SH SEE ALSO
|
|
\fBcurses\fR(3X),
|
|
\fBcurs_inopts\fR(3X),
|
|
\fBcurs_outopts\fR(3X),
|
|
\fBcurs_mouse\fR(3X),
|
|
\fBcurs_move\fR(3X),
|
|
\fBcurs_refresh\fR(3X),
|
|
\fBcurs_variables\fR(3X),
|
|
\fBresizeterm\fR(3X).
|
|
.PP
|
|
Comparable functions in the wide-character (ncursesw) library are
|
|
described in
|
|
\fBcurs_get_wch\fR(3X).
|