           getch,  wgetch,  mvgetch, mvwgetch, ungetch - 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
           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.

           If noecho has been set, then the character  will  also  be
           echoed into the designated window according to the follow-
           ing rules: If the character is the current  erase  charac-
           ter,  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

           The ungetch routine places ch back onto the input queue to
           be returned by the next call to wgetch.  Note  that  there
           is, in effect, 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.

           center tab(/) ; l l l l .  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/T{  Function  keys;
           space  for 64 keys is reserved.  T} KEY_F(n)/T{ For 0 <= n
           <=   63   T}   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_PREVI-
           OUS/Previous  object  key  KEY_REDO/Redo  key   KEY_REFER-
           ENCE/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_SCAN-
           CEL/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 mes-
           sage key KEY_SMOVE/Shifted move key KEY_SNEXT/Shifted next
           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  sus-
           pend  key  KEY_SUNDO/Shifted  undo key KEY_SUSPEND/Suspend
           key KEY_UNDO/Undo key

           Keypad is arranged like this:

           center allbox tab(/) ; c c  c  .   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 as the current  termi-
           nal type recognizes 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.

## 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.

           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 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-

           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.

## SEE ALSO

           curses(3X),        curs_inopts(3X),        curs_mouse(3X),
           curs_move(3X), curs_refresh(3X).  resizeterm(3X).