.TH curs_getch 3X ""
.SH NAME
\fBgetch\fR, \fBwgetch\fR, \fBmvgetch\fR,
\fBmvwgetch\fR, \fBungetch\fR - get (or push back) characters from
\fBcurses\fR terminal keyboard
.SH SYNOPSIS
\fB#include <curses.h>\fR
\fBint getch(void);\fR
.br
\fBint wgetch(WINDOW *win);\fR
.br
\fBint mvgetch(int y, int x);\fR
.br
\fBint mvwgetch(WINDOW *win, int y, int x);\fR
.br
\fBint ungetch(int ch);\fR
.br
.SH DESCRIPTION
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.
If \fBnoecho\fR has been set, then the character will also be echoed into the
designated window according to the following rules:
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.
If the character value is any other \fBKEY_\fR define, the user is alerted
with a \fBbeep\fR call.
Otherwise the character is simply output to the screen.
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.
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
intended to hold the return value of a function key must be of short size or
larger.
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.
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.
.nf
__________________________________________________________________
\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 Function keys; space for 64 keys is reserved.
KEY_F(\fIn\fR) For 0 \fI<\fR \fIn\fR \fI<\fR 63
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). Keypad is
arranged like this:
\fBA1\fR \fBup\fR \fBA3\fR
\fBleft\fR \fBB2\fR \fBright\fR
\fBC1\fR \fBdown\fR \fBC3\fR
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_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_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
.fi
.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
completion.
.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.
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.
Note that \fBgetch\fR, \fBmvgetch\fR, and \fBmvwgetch\fR may be macros.
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
These 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.
The echo behavior of these functions on input of \fBKEY_\fR or backspace
characters was not specified. This description is adopted from the XSI
Curses standard.
.SH SEE ALSO
\fBcurses\fR(3X), \fBcurs_inopts\fR(3X), \fBcurs_move\fR(3X),
\fBcurs_refresh\fR(3X).
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