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curs_getch(3X)                                                  curs_getch(3X)

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

       #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);

       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
       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 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 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.  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

   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_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 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.  See resizeterm(3X) for more
       details about KEY_RESIZE, and curs_mouse(3X) for a discussion of

       All routines return the integer ERR upon failure and an integer value
       other than ERR (OK in the case of ungetch()) upon successful

                   returns an error if there is no more room in the FIFO.

                   returns an error if the window pointer is null, or if its
                   timeout expires without having any data.

       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

       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_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
       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 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.

       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 conditionalized on the NCURSES_VERSION feature macro.

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

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



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