curs_outopts 3x 2024-05-11 ncurses 6.5 Library calls

curs_outopts(3x)                 Library calls                curs_outopts(3x)


       clearok,   idcok,   idlok,   immedok,   leaveok,  scrollok,  setscrreg,
       wsetscrreg - set curses output options


       #include <curses.h>

       int clearok(WINDOW *win, bool bf);
       void idcok(WINDOW *win, bool bf);
       int idlok(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);


       These routines set 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(3x).


       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.


       If idcok is called with FALSE as  second  argument,  curses  no  longer
       considers   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 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
       insertion  and  deletion.   This  option  should be enabled only if the
       application 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 applications  where  it  is  not  really
       needed.   If  insert/delete  line  cannot  be  used, curses redraws the
       changed portions of all lines.


       If immedok is called with TRUE as second argument, any  change  in  the
       window  image,  such  as  the  ones caused by waddch, wclrtobot, wscrl,
       etc., automatically causes a call to wrefresh.  However, it may degrade
       performance  considerably,  due to repeated calls to wrefresh.  Calling
       immedok with FALSE as second argument restores  the  default  behavior,
       i.e., deferring screen updates until a refresh is needed.


       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
       applications where the cursor is not used, since it  reduces  the  need
       for cursor motions.


       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
       character 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 terminal, 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
       parameters  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 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


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

       X/Open Curses does not specify 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 boundaries.


       Note that clearok, leaveok,  scrollok,  idcok,  and  setscrreg  may  be

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


       These functions are described in X/Open Curses, Issue 4.

       Some historic curses implementations had, as an  undocumented  feature,
       the  ability  to  do  the  equivalent  of  clearok(...,  1)  by  saying
       touchwin(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.  X/Open Curses does not  require  this,  and  ncurses
       avoids  doing  it  to  perform  better  vertical-motion optimization at
       wrefresh time.

       X/Open Curses 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 invisible.


       ncurses formerly treated nl(3x) and nonl(3x) as both input  and  output
       options, but no longer; see curs_inopts(3x).


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

ncurses 6.5                       2024-05-11                  curs_outopts(3x)