-.\" $Id: curs_getch.3x,v 1.10 1997/01/05 11:57:54 Jesse.Thilo Exp $
+'\" t
+.\"***************************************************************************
+.\" Copyright (c) 1998-2017,2018 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 1.53 2018/07/28 22:15:59 tom Exp $
.TH curs_getch 3X ""
+.na
+.hy 0
+.de bP
+.ie n .IP \(bu 4
+.el .IP \(bu 2
+..
.SH NAME
-\fBgetch\fR, \fBwgetch\fR, \fBmvgetch\fR,
-\fBmvwgetch\fR, \fBungetch\fR - get (or push back) characters from
-\fBcurses\fR terminal keyboard
+\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 *win);\fR
+\fBint wgetch(WINDOW *\fP\fIwin);\fR
.br
-\fBint mvgetch(int y, int x);\fR
+\fBint mvgetch(int \fP\fIy\fP\fB, int \fP\fIx\fP\fB);\fR
.br
-\fBint mvwgetch(WINDOW *win, int y, int x);\fR
+\fBint mvwgetch(WINDOW *\fP\fIwin\fP\fB, int \fP\fIy\fP\fB, int \fP\fIx\fP\fB);\fR
.br
-\fBint ungetch(int ch);\fR
+\fBint ungetch(int \fP\fIch\fP\fB);\fR
.br
-\fBint has_key(int ch);\fR
+\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
+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.
-
-If \fBnoecho\fR has been set, then the character will also be echoed into the
+.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. Possible function
-keys are defined in \fB<curses.h>\fR as macros with values outside the range
-of 8-bit characters whose names begin with \fBKEY_.\fR Thus, a variable
+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
+(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. Note that there is, in effect,
-just one input queue for all windows.
-
-.SS Function Keys
-The following function keys, defined in \fB<curses.h>\fR, might be returned by
-\fBgetch\fR if \fBkeypad\fR has been enabled. Note that not all of these are
-necessarily supported on any particular terminal.
-.sp
+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
l l .
\fIName\fR/\fIKey\fR \fIname\fR
-
+_
KEY_BREAK/Break key
KEY_DOWN/The four arrow keys ...
KEY_UP
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_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_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_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_SUSPEND/Suspend key
KEY_UNDO/Undo key
.TE
-
+.PP
Keypad is arranged like this:
-.sp
+.br
.TS
center allbox tab(/) ;
c c c .
\fBC1\fR/\fBdown\fR/\fBC3\fR
.TE
.sp
-The \fBhas_key\fR routine takes a key value from the above list, and
-returns TRUE or FALSE according as the current terminal type recognizes
-a key with that value.
-
+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 ungetch()) upon successful
+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
+(\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
+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
+\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
+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
+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
+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 hsd been set.
-
+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 ERR with \fBerrno\fR set to
-\fBEINTR\fR. Under the \fBncurses\fR implementation, handled signals never
-interrupt \fBgetch\fR.
-
-The \fBhas_key\fR function is unique to \fBncurses\fR. We recommend that
-any code using it be conditionalized on the NCURSES feature macro.
+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_move\fR(3X),
-\fBcurs_refresh\fR(3X).
-.\"#
-.\"# The following sets edit modes for GNU EMACS
-.\"# Local Variables:
-.\"# mode:nroff
-.\"# fill-column:79
-.\"# End:
+\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).
projects / ncurses.git / blobdiff