keypad(3XCURSES) X/Open Curses Library Functions keypad(3XCURSES)
NAME
keypad - enable/disable keypad handling
SYNOPSIS
cc [ flag... ] file... -I /usr/xpg4/include -L /usr/xpg4/lib
-R /usr/xpg4/lib -lcurses [ library... ]
c89 [ flag... ] file... -lcurses [ library... ]
#include <curses.h>
int keypad(WINDOW *win, bool bf);
PARAMETERS
win Is a pointer to the window in which to enable/disable keypad handling.
bf Is a Boolean expression.
DESCRIPTION
The keypad() function controls keypad translation. If bf is TRUE, keypad translation is enabled. If bf is FALSE, keypad translation is dis-
abled. The initial state is FALSE.
This function affects the behavior of any function that provides keyboard input.
If the terminal in use requires a command to enable it to transmit distinctive codes when a function key is pressed, then after keypad
translation is first enabled, the implementation transmits this command to the terminal before an affected input function tries to read any
characters from that terminal.
The Curses input model provides the following ways to obtain input from the keyboard:
Keypad processing
The application can enable or disable keypad translation by calling keypad(). When translation is enabled, Curses attempts to translate a
sequence of terminal input that represents the pressing of a function into a single key code. When translation is disabled, Curses passes
terminal input to the application without such translation, and any interpretation of the input as representing the pressing of a keypad
key must be done by the application.
The complete set of key codes for keypad keys that Curses can process is specified by the constants defined in <curses.h> whose names begin
with "KEY_". Each terminal type described in the terminfo database may support some or all of these key codes. The terminfo database speci-
fies the sequence of input characters from the terminal type that correspond to each key code.
The Curses inplementation cannot translate keypad keys on terminals where pressing the keys does not transmit a unique sequence.
When translation is enabled and a character that could be the beginning of a function key (such as escape) is received, Curses notes the
time and begins accumulating characters. If Curses receives additional characters that represent the processing of a keypad key within an
unspecified interval from the time the character was received, then Curses converts this input to a key code for presentation to the appli-
cation. If such characters are not received during this interval, translation of this input does not occur and the individual characters
are presented to the application separately. (Because Curses waits for this interval to accumulate a key code, many terminals experience a
delay between the time a user presses the escape key and the time the escape key is returned to the application.)
In addition, No Timeout Mode provides that in any case where Curses has received part of a function key sequence, it waits indefinitely for
the complete key sequence. The "unspecified interval" in the previous paragraph becomes infinite in No Timeout Mode. No Timeout Mode allows
the use of function keys over slow communication lines. No Timeout Mode lets the user type the individual characters of a function key
sequence, but also delays application response when the user types a character (not a function key) that begins a function key sequence.
For this reason, in No Timeout Mode many terminals will appear to hang between the time a user presses the escape key and the time another
key is pressed. No Timeout Mode is switchable by calling notimeout(3XCURSES).
If any special characters (<backspace>, <carriage return>, <newline>, <tab>) are defined or redefined to be characters that are members of
a function key sequence, then Curses will be unable to recognize and translate those function keys.
Several of the modes discussed below are described in terms of availability of input. If keypad translation is enabled, then input is not
available once Curses has begun receiving a keypad sequence until the sequence is completely received or the interval has elapsed.
Input Mode
The following four mutually-specific Curses modes let the application control the effect of flow-control characters, the interrupt charac-
ter, the erase character, and the kill character:
+------------------------------------------------------------+
| Input Mode Effect |
|Cooked Mode This achieves normal line-at-a-time pro- |
| cessing with all special characters han- |
| dled outside the application. This |
| achieves the same effect as canonical- |
| mode input processing. The state of the |
| ISIG and IXON flags are not changed upon |
| entering this mode by calling |
| nocbreak(3XCURSES), and are set upon |
| entering this mode by calling |
| noraw(3XCURSES).Erase and kill characters |
| are supported from any supported locale, |
| no matter the width of the character. |
|cbreak Mode Characters typed by the user are immedi- |
| ately available to the application and |
| Curses does not perform special process- |
| ing on either the erase character or the |
| kill character. An application can set |
| cbreak mode to do its own line editing |
| but to let the abort character be used to |
| abort the task. This mode achieves the |
| same effect as non-canonical-mode, Case B |
| input processing (with MIN set to 1 and |
| ICRNL cleared.) The state of the ISIG and |
| IXON flags are not changed upon entering |
| this mode. |
|Half-Delay Mode The effect is the same as cbreak, except |
| that input functions wait until a charac- |
| ter is available or an interval defined |
| by the application elapses, whichever |
| comes first. This mode achieves the same |
| effect as non-canonical-mode, Case C |
| input processing (with TIME set to the |
| value specified by the application.) The |
| state of the ISIG and IXON flags are not |
| changed upon entering this mode. |
|Raw Mode Raw mode gives the application maximum |
| control over terminal input. The applica- |
| tion sees each character as it is typed. |
| This achieves the same effect as non- |
| canonical mode, Case D input processing. |
| The ISIG and IXON flags are cleared upon |
| entering this mode. |
+------------------------------------------------------------+
The terminal interface settings are reported when the process calls initscr(3XCURSES) or newterm(3XCURSES) to initialize Curses and
restores these settings when endwin(3XCURSES) is called. The initial input mode for Curses operations is especially unless Enhanced Curses
compliance, in which the initial mode is cbreak mode, is supported.
The behavior of the BREAK key depends on other bits in the display driver that are not set by Curses.
Delay Mode
Two mutually-exclusive delay modes specify how quickly certain Curses functions return to the application when there is no terminal input
waiting when the function is called:
No Delay The function fails.
Delay The application waits until text is passed through to the application. If cbreak or Raw Mode is set, this is after one charac-
ter. Otherwise, this is after the first <newline> character, end-of-line character, or end-of-file character.
The effect of No Delay Mode on function key processing is unspecified.
Echo processing
Echo mode determines whether Curses echoes typed characters to the screen. The effect of Echo mode is analogous to the effect of the ECHO
flag in the local mode field of the termios structure associated with the terminal device connected to the window. However, Curses always
clears the ECHO flag when invoked, to inhibit the operating system from performing echoing. The method of echoing characters is not identi-
cal to the operating system's method of echoing characters, because Curses performs additional processing of terminal input.
If in Echo mode, Curses performs 's's own echoing. Any visible input character is stored in the current or specified window by the input
function that the application called, at that window's cursor position, as though addch(3XCURSES) were called, with all consequent effects
such as cursor movement and wrapping.
If not in Echo mode, any echoing of input must be performed by the application. Applications often perform their own echoing in a con-
trolled area of the screen, or do not echo at all, so they disable Echo mode.
It may not be possible to turn off echo processing for synchronous and networked asynchronous terminals because echo processing is done
directly by the terminals. Applications running on such terminals should be aware that any characters typed will appear on the screen at
wherever the cursor is positioned.
RETURN VALUES
Upon successful completion, the keypad() function returns OK. Otherwise, it returns ERR.
ERRORS
No errors are defined.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
|MT-Level |Unsafe |
+-----------------------------+-----------------------------+
SEE ALSO
addch(3XCURSES), endwin(3XCURSES), getch(3XCURSES), initscr(3XCURSES), libcurses(3XCURSES), newterm(3XCURSES), nocbreak(3XCURSES),
noraw(3XCURSES), attributes(5), standards(5)
SunOS 5.11 5 Jun 2002 keypad(3XCURSES)