curs_outopts 3x 2023-09-30 ncurses 6.4 Library calls

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


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


       #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);


       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 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 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 immedok is called with TRUE as argument, any change  in  the  window
       image,  such  as  the  ones  caused  by waddch, wclrtobot, wscrl, etc.,
       automatically cause a  call  to  wrefresh.   However,  it  may  degrade
       performance  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  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).


       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 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
       returns an error if the window pointer is null.


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

       From the outset, ncurses used nl/nonl  to  control  the  conversion  of
       newlines  to carriage return/line-feed on output as well as input.  XSI
       Curses documents only the use  of  these  functions  for  input.   This
       difference  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.
       Because  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
       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.  XSI Curses does not require this, and ncurses avoids
       doing  it  to  perform  better vertical-motion optimization at wrefresh

       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


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

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


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

ncurses 6.4                       2023-09-30                  curs_outopts(3x)