+ The getch, wgetch, mvgetch and mvwgetch, routines read a character from
+ the window. In no-delay mode, if no input is waiting, the value ERR is
+ returned. In delay mode, the program waits until the system passes
+ text through to the program. Depending on the setting of cbreak, this
+ is after one character (cbreak mode), or after the first newline
+ (nocbreak mode). In half-delay mode, the program waits until a charac-
+ ter is typed or the specified timeout has been reached.
+
+ If echo is enabled, and the window is not a pad, then the character
+ will also be echoed into the designated window according to the follow-
+ ing rules:
+
+ o 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 delch had been called.
+
+ o If the character value is any other KEY_ define, the user is alert-
+ ed with a beep call.
+
+ o If the character is a carriage-return, and if nl is enabled, it is
+ translated to a line-feed after echoing.
+
+ o 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 wrefresh, wrefresh will be called before another character
+ is read.
+
+
+
+ If keypad is TRUE, and a function key is pressed, the token for that
+ function key is returned instead of the raw characters:
+
+ o The predefined function keys are listed in <curses.h> as macros
+ with values outside the range of 8-bit characters. Their names be-
+ gin with KEY_.
+
+ o Other (user-defined) function keys which may be defined using de-
+ fine_key(3x) have no names, but also are expected to have values
+ outside the range of 8-bit characters.
+
+ 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 re-
+ ceived (which, on modern terminals, means an escape character), curses
+ 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 expe-
+ rience a delay between the time a user presses the escape key and the
+ escape is returned to the program.
+
+ In ncurses, the timer normally expires after the value in ESCDELAY (see
+ curs_variables(3x)). If notimeout is TRUE, 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 no-
+ timeout mode after pressing the escape key until another key is
+ pressed.
+
+
+
+ The ungetch routine places ch back onto the input queue to be returned
+ by the next call to wgetch. There is just one input queue for all win-
+ dows.
+
+
+
+ The following special keys are defined in <curses.h>.
+
+ o Except for the special case KEY_RESIZE, it is necessary to enable
+ keypad for getch to return these codes.
+
+ o Not all of these are necessarily supported on any particular termi-
+ nal.
+
+ o The naming convention may seem obscure, with some apparent mis-
+ spellings (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.
+
+ NameKeyname
+ -------------------------------------------------
+ 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(n) For 0 <= n <= 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)
+ 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
+ Keypad is arranged like this:
-
-
DESCRIPTION
- The getch, wgetch, mvgetch and mvwgetch, routines read a
- character from the window. In no-delay mode, if no input
- is waiting, the value ERR is returned. In delay mode, the
- program waits until the system passes text through to the
- program. Depending on the setting of cbreak, this is
- after one character (cbreak mode), or after the first new-
- line (nocbreak mode). In half-delay mode, the program
- waits until a character is typed or the specified timeout
- has been reached.
-
- Unless noecho has been set, then the character will also
- be echoed into the designated window according to the fol-
- lowing rules: If the character is the current erase char-
- acter, left arrow, or backspace, the cursor is moved one
- space to the left and that screen position is erased as if
- delch had been called. If the character value is any
- other KEY_ define, the user is alerted with a beep call.
- Otherwise the character is simply output to the screen.
-
- If the window is not a pad, and it has been moved or modi-
- fied since the last call to wrefresh, wrefresh will be
- called before another character is read.
-
- If keypad is TRUE, 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
- <curses.h> as macros with values outside the range of
- 8-bit characters whose names begin with KEY_. 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), curses 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 ungetch routine places ch back onto the input queue to
- be returned by the next call to wgetch. There is just one
- input queue for all windows.
-
-
- FunctionKeys
- The following function keys, defined in <curses.h>, might
- be returned by getch if keypad has been enabled. Note
- that not all of these are necessarily supported on any
- particular terminal.
-
- NameKeyname
-
- 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(n) For 0 <= n <= 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).
- 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
+ +-----+------+-------+
+ | A1 | up | A3 |
+ +-----+------+-------+
+ |left | B2 | right |
+ +-----+------+-------+
+ | C1 | down | C3 |
+ +-----+------+-------+
+ A few of these predefined values do not correspond to a real key:
- Keypad is arranged like this:
+ oKEY_RESIZE is returned when the SIGWINCH signal has been detected
+ (see initscr(3x) and resizeterm(3x)). This code is returned
+ whether or not keypad has been enabled.
- +-----+------+-------+
- | A1 | up | A3 |
- +-----+------+-------+
- |left | B2 | right |
- +-----+------+-------+
- | C1 | down | C3 |
- +-----+------+-------+
- The has_key routine takes a key value from the above list,
- and returns TRUE or FALSE according to whether the current
- terminal type recognizes a key with that value.
+ oKEY_MOUSE is returned for mouse-events (see curs_mouse(3x)). This
+ code relies upon whether or not keypad(3x) has been enabled, be-
+ cause (e.g., with xterm mouse prototocol) ncurses must read escape
+ sequences, just like a function key.
+
+ The has_key routine takes a key-code value from the above list, and re-
+ turns TRUE or FALSE according to whether the current terminal type rec-
+ ognizes a key with that value.
-
-
RETURN VALUE
- All routines return the integer ERR upon failure and an
- integer value other than ERR (OK in the case of ungetch())
- upon successful completion.
+ The library also supports these extensions:
+ define_key
+ defines a key-code for a given string (see define_key(3x)).
-
-
NOTES
- Use of the escape key by a programmer for a single charac-
- ter function is discouraged, as it will cause a delay of
- up to one second while the keypad code looks for a follow-
- ing function-key sequence.
-
- Note that some keys may be the same as commonly used con-
- trol keys, e.g., KEY_ENTER versus control/M, KEY_BACKSPACE
- versus control/H. Some curses implementations may differ
- according to whether they treat these control keys spe-
- cially (and ignore the terminfo), or use the terminfo def-
- initions. Ncurses uses the terminfo definition. If it
- says that KEY_ENTER is control/M, getch, will return
- KEY_ENTER when you press control/M.
-
- When using getch, wgetch, mvgetch, or mvwgetch, nocbreak
- mode (nocbreak) and echo mode (echo) 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.
+ key_defined
+ checks if there is a key-code defined for a given string (see
+ key_defined(3x)).
- Note that getch, mvgetch, and mvwgetch 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 KEY_UP,
- KEY_DOWN, KEY_LEFT, KEY_RIGHT, KEY_HOME, KEY_END,
- KEY_NPAGE, KEY_PPAGE, and function keys 1 through 12. The
- Ins key is usually mapped to KEY_IC.
+
+ All routines return the integer ERR upon failure and an integer value
+ other than ERR (OK in the case of ungetch) upon successful completion.
+ ungetch
+ returns ERR if there is no more room in the FIFO.
-
-
PORTABILITY
- The *get* functions are described in the XSI Curses stan-
- dard, Issue 4. They read single-byte characters only.
- The standard specifies that they return ERR on failure,
- but specifies no error conditions.
-
- The echo behavior of these functions on input of KEY_ or
- backspace characters was not specified in the SVr4 docu-
- mentation. This description is adopted from the XSI
- Curses standard.
-
- The behavior of getch and friends in the presence of han-
- dled 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
- read(2) call in progress or not, and also (in some imple-
- mentations) depending on whether an input timeout or non-
- blocking mode hsd been set.
-
- Programmers concerned about portability should be prepared
- for either of two cases: (a) signal receipt does not
- interrupt getch; (b) signal receipt interrupts getch and
- causes it to return ERR with errno set to EINTR. Under
- the ncurses implementation, handled signals never inter-
- rupt getch.
-
- The has_key function is unique to ncurses. We recommend
- that any code using it be conditionalized on the
- NCURSES_VERSION feature macro.
+ wgetch
+ returns ERR if the window pointer is null, or if its timeout
+ expires without having any data, or if the execution was inter-
+ rupted by a signal (errno will be set to EINTR).
+ Functions with a "mv" prefix first perform a cursor movement using
+ wmove, and return an error if the position is outside the window, or if
+ the window pointer is null.
-
+ 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.
+
+ Some keys may be the same as commonly used control keys, e.g., KEY_EN-
+ TER versus control/M, KEY_BACKSPACE versus control/H. Some curses im-
+ plementations may differ according to whether they treat these control
+ keys specially (and ignore the terminfo), or use the terminfo defini-
+ tions. Ncurses uses the terminfo definition. If it says that KEY_EN-
+ TER is control/M, getch will return KEY_ENTER when you press control/M.
+ Generally, KEY_ENTER denotes the character(s) sent by the Enter key on
+ the numeric keypad:
+ o the terminal description lists the most useful keys,
+ o the Enter key on the regular keyboard is already handled by the
+ standard ASCII characters for carriage-return and line-feed,
+ o depending on whether nl or nonl was called, pressing "Enter" on the
+ regular keyboard may return either a carriage-return or line-feed,
+ and finally
+
+ o "Enter or send" is the standard description for this key.
+
+ When using getch, wgetch, mvgetch, or mvwgetch, nocbreak mode
+ (nocbreak) and echo mode (echo) 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 getch, mvgetch, and mvwgetch may be macros.
+ Historically, the set of keypad macros was largely defined by the ex-
+ tremely function-key-rich keyboard of the AT&T 7300, aka 3B1, aka Sa-
+ fari 4. Modern personal computers usually have only a small subset of
+ these. IBM PC-style consoles typically support little more than
+ KEY_UP, KEY_DOWN, KEY_LEFT, KEY_RIGHT, KEY_HOME, KEY_END, KEY_NPAGE,
+ KEY_PPAGE, and function keys 1 through 12. The Ins key is usually
+ mapped to KEY_IC.
+
+ The *get* functions are described in the XSI Curses standard, Issue 4.
+ They read single-byte characters only. The standard specifies that
+ they return ERR on failure, but specifies no error conditions.
+ The echo behavior of these functions on input of KEY_ or backspace
+ characters was not specified in the SVr4 documentation. This descrip-
+ tion is adopted from the XSI Curses standard.
+ The behavior of getch 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 read(2)
+ call in progress or not, and also (in some implementations) depending
+ on whether an input timeout or non-blocking mode has been set.
+ KEY_MOUSE is mentioned in XSI Curses, along with a few related terminfo
+ capabilities, but no higher-level functions use the feature. The im-
+ plementation in ncurses is an extension.
+ KEY_RESIZE is an extension first implemented for ncurses. NetBSD curs-
+ es later added this extension.
+ Programmers concerned about portability should be prepared for either
+ of two cases: (a) signal receipt does not interrupt getch; (b) signal
+ receipt interrupts getch and causes it to return ERR with errno set to
+ EINTR.
+ The has_key function is unique to ncurses. We recommend that any code
+ using it be conditionalized on the NCURSES_VERSION feature macro.
+