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curs_getch(3x) - getch, has_key, mvgetch, mvwgetch, ungetch, wgetch - get (or push back) characters from curses terminal keyboard - man 3x curs_getch

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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(2,n,1 builtins) a character from
       the window.  In no-delay mode, if(3,n) 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(1,3x,3x cbreak) has been reached.

       Unless noecho has been set(7,n,1 builtins), then the character will also be echoed into
       the  designated window according to the following rules: If the charac-
       ter is the current erase character, left arrow, or backspace, the  cur-
       sor  is  moved one space to the left and that screen position is erased
       as if(3,n) delch had been called.  If the character value is any other  KEY_
       define,  the user is alerted with a beep(1,3x,3x curs_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 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(3x,7,8,3x cbreak) characters.  Possible func-
       tion keys are defined in(1,8) <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(1,8)
       within the designated time(1,2,n), the character is passed through; otherwise,
       the  function  key  value is returned.  For this reason, many terminals
       experience a delay between the time(1,2,n) a user presses the escape  key  and
       the escape is returned to the program.

       The  ungetch routine places ch back onto the input queue(1,3) to be returned
       by the next call to wgetch.  There is just one input queue(1,3) for all win-
       dows.


   Function Keys
       The  following  function keys, defined in(1,8) <curses.h>, might be returned
       by getch if(3,n) 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(2,n)
                  KEY_SRESET      Soft (partial) reset(1,7,1 tput)
                  KEY_RESET       Reset or hard reset(1,7,1 tput)
                  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(2,n,1 builtins)
                  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(1,3x,3x clrtobot) line key
                  KEY_SEXIT       Shifted exit(3,n,1 builtins) 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(3x,7,3x curs_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 according 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.


RETURN VALUE
       All  routines  return the integer ERR upon failure and an integer value
       other than ERR (OK in(1,8) the case of ungetch())  upon  successful  comple-
       tion.

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 according 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_ENTER is control/M, getch will return KEY_ENTER when you press con-
       trol/M.

       When   using   getch,  wgetch,  mvgetch,  or  mvwgetch,  nocbreak  mode
       (nocbreak) and echo(1,3x,1 builtins) mode (echo(1,3x,1 builtins)) should not be used at  the  same  time.
       Depending  on the state of the tty(1,4) driver when each character is typed,
       the program may produce undesirable results.

       Note that getch, mvgetch, and mvwgetch may be macros.

       Historically, the set(7,n,1 builtins) 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(1,8) the XSI Curses standard, Issue  4.
       They  read(2,n,1 builtins)  single-byte  characters  only.  The standard specifies that
       they return ERR on failure, but specifies no error(8,n) conditions.

       The echo(1,3x,1 builtins) behavior of these functions on  input  of  KEY_  or  backspace
       characters  was not specified in(1,8) the SVr4 documentation.  This descrip-
       tion is adopted from the XSI Curses standard.

       The behavior of getch and friends in(1,8) the presence of handled signals is
       unspecified in(1,8) the SVr4 and XSI Curses documentation.  Under historical
       curses implementations, it varied depending on  whether  the  operating
       system's  implementation of handled signal(2,7) receipt interrupts a read(2,n,1 builtins)(2)
       call in(1,8) progress or not, and also (in(1,8) some  implementations)  depending
       on whether an input timeout(1,3x,3x cbreak) or non-blocking mode has been set.

       Programmers  concerned  about portability should be prepared for either
       of two cases: (a) signal(2,7) receipt does not interrupt getch;  (b)  signal(2,7)
       receipt  interrupts getch and causes it to return ERR with errno set(7,n,1 builtins) 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).



                                                                curs_getch(3X)

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