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.
       __________________________________________________________________
       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).  Keypad is
                            arranged like this:
                                 A1    up    A3
                                left   B2   right
                                 C1   down   C3
       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_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

       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-
       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-
       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
       feature macro.


SEE ALSO

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