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scrollok(3x) - clearok, idcok, idlok, immedok, leaveok, nl, nonl, scrollok, setscrreg, wsetscrreg - curses output options - man 3x scrollok

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curs_outopts(3X)                                              curs_outopts(3X)



NAME
       clearok,  idlok, idcok, immedok, leaveok, setscrreg, wsetscrreg, scrol-
       lok, nl(1,3x,3x clearok), nonl - curses output options

SYNOPSIS
       #include <curses.h>

       int clearok(WINDOW *win, bool bf);
       int idlok(WINDOW *win, bool bf);
       void idcok(WINDOW *win, bool bf);
       void immedok(WINDOW *win, bool bf);
       int leaveok(WINDOW *win, bool bf);
       int setscrreg(int top, int bot);
       int wsetscrreg(WINDOW *win, int top, int bot);
       int scrollok(WINDOW *win, bool bf);
       int nl(1,3x,3x clearok)(void);
       int nonl(void);

DESCRIPTION
       These routines set(7,n,1 builtins) options that  change  the  style  of  output  within
       curses.   All options are initially FALSE, unless otherwise stated.  It
       is not necessary to turn these options off before calling endwin.

       If clearok is called with TRUE as argument, the next call  to  wrefresh
       with this window will clear(1,3x,3x clrtobot) the screen completely and redraw the entire
       screen from scratch.  This is useful when the contents  of  the  screen
       are  uncertain, or in(1,8) some cases for a more pleasing visual effect.  If
       the win argument to clearok is the global  variable  curscr,  the  next
       call  to  wrefresh  with any window causes the screen to be cleared and
       repainted from scratch.

       If idlok is called with TRUE as second argument, curses considers using
       the  hardware  insert/delete  line  feature  of  terminals so equipped.
       Calling idlok with FALSE as second argument disables use of line inser-
       tion  and deletion.  This option should be enabled only if(3,n) the applica-
       tion needs insert/delete line, for example, for a screen editor.  It is
       disabled  by  default  because  insert/delete line tends to be visually
       annoying when used in(1,8) applications where it isn't  really  needed.   If
       insert/delete  line cannot be used, curses redraws the changed portions
       of all lines.

       If idcok is called with FALSE as second argument, curses no longer con-
       siders  using the hardware insert/delete character feature of terminals
       so equipped.  Use of character insert/delete  is  enabled  by  default.
       Calling  idcok with TRUE as second argument re-enables use of character
       insertion and deletion.

       If immedok is called with TRUE as argument, any change  in(1,8)  the  window
       image, such as the ones caused by waddch, wclrtobot, wscrl, etc., auto-
       matically cause a call to wrefresh.  However, it  may  degrade  perfor-
       mance  considerably, due to repeated calls to wrefresh.  It is disabled
       by default.

       Normally, the hardware cursor is left at the  location  of  the  window
       cursor  being  refreshed.   The  leaveok option allows the cursor to be
       left wherever the update(7,n) happens to leave it.  It is useful for  appli-
       cations  where  the  cursor  is not used, since it reduces the need for
       cursor motions.

       The setscrreg and wsetscrreg routines allow the application  programmer
       to  set(7,n,1 builtins)  a  software scrolling region in(1,8) a window.  top and bot are the
       line numbers of the top and bottom  margin  of  the  scrolling  region.
       (Line  0  is  the top line of the window.)  If this option and scrollok
       are enabled, an attempt to move(3x,7,3x curs_move) off the bottom margin line  causes  all
       lines  in(1,8)  the  scrolling region to scroll one line in(1,8) the direction of
       the first line.  Only the text of the window is scrolled.   (Note  that
       this  has  nothing  to  do  with the use of a physical scrolling region
       capability in(1,8) the terminal, like  that  in(1,8)  the  VT100.   If  idlok  is
       enabled and the terminal has either a scrolling region or insert/delete
       line capability, they will probably be used by the output routines.)

       The scrollok option controls what happens when the cursor of  a  window
       is  moved  off  the edge of the window or scrolling region, either as a
       result of a newline action on the bottom line, or typing the last char-
       acter of the last line.  If disabled, (bf is FALSE), the cursor is left
       on the bottom line.  If enabled, (bf is TRUE), the window  is  scrolled
       up one line (Note that to get the physical scrolling effect on the ter-
       minal, it is also necessary to call idlok).

       The nl(1,3x,3x clearok) and nonl routines control whether the underlying display  device
       translates  the return key into newline on input, and whether it trans-
       lates newline into return and line-feed on output (in(1,8) either case,  the
       call  addch('\n')  does  the  equivalent of return and line feed on the
       virtual(5,8) screen).  Initially, these translations do occur.  If you  dis-
       able  them  using  nonl,  curses will be able to make better use of the
       line-feed capability, resulting in(1,8) faster cursor motion.  Also,  curses
       will then be able to detect the return key.

RETURN VALUE
       The  functions  setscrreg and wsetscrreg return OK upon success and ERR
       upon failure.  All other routines that return an integer always  return
       OK.

PORTABILITY
       These functions are described in(1,8) the XSI Curses standard, Issue 4.

       The  XSI  Curses standard is ambiguous on the question of whether raw(3x,7,8,3x cbreak)()
       should disable the CRLF translations controlled  by  nl(1,3x,3x clearok)()  and  nonl().
       BSD  curses  did  turn off these translations; AT&T curses (at least as
       late as SVr1) did not.  We choose to do so, on the theory that  a  pro-
       grammer  requesting  raw(3x,7,8,3x cbreak) input wants a clean (ideally 8-bit clean) con-
       nection that the operating system does not mess with.

       Some historic curses implementations had, as an  undocumented(2,3)  feature,
       the  ability  to  do the equivalent of clearok(..., 1) by saying touch-
       win(stdscr) or clear(1,3x,3x clrtobot)(stdscr).  This will not work under ncurses.

       Earlier System V curses implementations specified  that  with  scrollok
       enabled,  any  window  modification  triggering  a scroll also forced a
       physical refresh.  XSI Curses does not require this, and ncurses avoids
       doing  it  to  perform  better vertical-motion optimization at wrefresh
       time.

       The XSI Curses standard does not mention that the cursor should be made
       invisible  as a side-effect of leaveok.  SVr4 curses documentation does
       this, but the code does not.  Use curs_set to make the  cursor  invisi-
       ble.

NOTES
       Note that clearok, leaveok, scrollok, idcok, nl(1,3x,3x clearok), nonl and setscrreg may
       be macros.

       The immedok routine is useful for windows that  are  used  as  terminal
       emulators.

SEE ALSO
       curses(3X),     curs_addch(3X),    curs_clear(3X),    curs_initscr(3X),
       curs_scroll(3X), curs_refresh(3X)



                                                              curs_outopts(3X)

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