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curs_getch(3X)									   curs_getch(3X)

NAME
       getch, wgetch, mvgetch, mvwgetch, ungetch, has_key - get (or push back) characters from
       curses terminal keyboard

SYNOPSIS
       #include <curses.h>

       int getch(void);
       int wgetch(WINDOW *win);
       int mvgetch(int y, int x);
       int mvwgetch(WINDOW *win, int y, int x);
       int ungetch(int ch);
       int has_key(int ch);

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 pro-
       gram 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 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 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 posi-
       tion is erased as if delch had been called.  If the character value is any other KEY_  de-
       fine,  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 modified since the last call to  wre-
       fresh, 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 re-
       turned 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 mod-
       ern 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.

   Function Keys
       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.

			    Name	    Key name
			    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:

					 +-----+------+-------+
					 | 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  ac-
       cording	to whether the current terminal type recognizes a key with that value.	Note that
       a few values do not correspond to a real key, e.g., KEY_RESIZE  and  KEY_MOUSE.	 See  re-
       sizeterm(3X)  for  more	details  about KEY_RESIZE, and curs_mouse(3X) for a discussion of
       KEY_MOUSE.

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.

	  ungetch
	       returns ERR if there is no more room in the FIFO.

	  wgetch
	       returns	ERR if the window pointer is null, or if its timeout expires without hav-
	       ing any data.

       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.

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.

       Note  that some keys may be the same as commonly used control keys, e.g., KEY_ENTER versus
       control/M, KEY_BACKSPACE versus control/H.  Some curses implementations may differ accord-
       ing  to	whether they treat these control keys specially (and ignore the terminfo), or use
       the terminfo definitions.  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 charac-
	   ters 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 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.

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 ERR on failure, but  speci-
       fies no error conditions.

       The  echo  behavior  of	these  functions on input of KEY_ or backspace characters was not
       specified in the SVr4 documentation.  This description 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 de-
       pending	on whether the operating system's implementation of handled signal receipt inter-
       rupts 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.

       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 interrupt getch.

       The has_key function is unique to ncurses.  We recommend that any code using it be  condi-
       tionalized on the NCURSES_VERSION feature macro.

SEE ALSO
       curses(3X),  curs_inopts(3X),  curs_outopts(3X),  curs_mouse(3X),  curs_move(3X), curs_re-
       fresh(3X), resizeterm(3X).

       Comparable  functions  in  the  wide-character  (ncursesw)  library   are   described   in
       curs_get_wch(3X).

										   curs_getch(3X)
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