# curs_outopts 3x

    curs_outopts(3x)                                              curs_outopts(3x)

## NAME

           clearok, idlok, idcok, immedok, leaveok, setscrreg, wsetscrreg,
           scrollok - 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 scrollok(WINDOW *win, bool bf);

           int setscrreg(int top, int bot);
           int wsetscrreg(WINDOW *win, int top, int bot);

## DESCRIPTION

           These routines set options that change the style of output within curs-
           es.   All  options are initially FALSE, unless otherwise stated.  It is
           not necessary to turn these options off before calling endwin(3x).

### clearok

           If clearok is called with TRUE as argument, the next call  to  wrefresh
           with this window will clear the screen completely and redraw the entire
           screen from scratch.  This is useful when the contents  of  the  screen
           are  uncertain, or in 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.

### idlok

           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 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 an-
           noying when used in applications where it is not really needed.  If in-
           sert/delete line cannot be used, curses redraws the changed portions of
           all lines.

### idcok

           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.

### immedok

           If immedok is called with TRUE as argument, any change  in  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.

### leaveok

           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 happens to leave it.  It is useful for  appli-
           cations  where  the  cursor  is not used, since it reduces the need for
           cursor motions.

### scrollok

           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).

### setscrreg/wsetscrreg

           The setscrreg and wsetscrreg routines allow the application  programmer
           to set a software scrolling region in a window.  The top and bot param-
           eters 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 op-
           tion and scrollok are enabled, an attempt to move off the bottom margin
           line causes all lines in the scrolling region to scroll one line in 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 the terminal, like that in 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.)

## 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.

           X/Open Curses does not define any error conditions.

           In this implementation,

           o   those functions that have a window pointer will return an error  if
               the window pointer is null

           o   wsetscrreg  returns  an error if the scrolling region limits extend
               outside the window.

           X/Open does not define any error conditions.  This  implementation  re-
           turns an error if the window pointer is null.

## PORTABILITY

           These functions are described in the XSI Curses standard, Issue 4.

           From the outset, ncurses used nl/nonl to control the conversion of new-
           lines to carriage return/line-feed on output as  well  as  input.   XSI
           Curses  documents only the use of these functions for input.  This dif-
           ference arose from converting the  pcurses  source  (which  used  ioctl
           calls  with  the sgttyb structure) to termios (i.e., the POSIX terminal
           interface).  In the former, both input and output were controlled via a
           single  option  CRMOD,  while the latter separates these features.  Be-
           cause that conversion interferes with output optimization, nl/nonl were
           amended after ncurses 6.2 to eliminate their effect on output.

           Some  historic  curses implementations had, as an undocumented feature,
           the ability to do the equivalent of clearok(..., 1)  by  saying  touch-
           win(stdscr) or clear(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,  and  setscrreg  may  be
           macros.

           The immedok routine is useful for windows that are used as terminal em-
           ulators.

## SEE ALSO

           curses(3x), curs_addch(3x), curs_clear(3x), curs_initscr(3x),
           curs_scroll(3x), curs_refresh(3x), curs_variables(3x).

                                                                  curs_outopts(3x)