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NAME    [Toc]    [Back]

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

SYNOPSIS    [Toc]    [Back]

       #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(void);
       int nonl(void);

DESCRIPTION    [Toc]    [Back]

       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.

       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 isn't really needed.  If insert/delete line  cannot
  be  used,  curses redraws the changed portions of all

       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 wre-
       fresh.  However, it may degrade performance  considerably,
       due  to  repeated  calls  to  wrefresh.  It is disabled by

       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.   If  possible, the cursor is made invisible when
       this option is enabled.

       The setscrreg and wsetscrreg routines allow  the  application
  programmer  to  set a software scrolling region in 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 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.)

       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 in order to get the
       physical scrolling effect on the terminal, it is also necessary
 to call idlok).

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

RETURN VALUE    [Toc]    [Back]

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

PORTABILITY    [Toc]    [Back]

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

       The  XSI  Curses  standard is ambiguous on the question of
       whether raw() should disable the  CRLF  translations  controlled
 by nl() 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 programmer
       requesting raw input wants a clean (ideally  8-bit  clean)
       connection that the operating system does not mess with.

       Some  historic  curses  implementations had, as an undocumented
 feature,  the  ability  to  do  the  equivalent  of
       clearok(...,  1)  by saying touchwin(stdscr) or clear(std-
       scr).  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 in order 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 invisible.

NOTES    [Toc]    [Back]

       Note that clearok, leaveok, scrollok, idcok, nl, nonl  and
       setscrreg may be macros.

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

SEE ALSO    [Toc]    [Back]

       curses(3), curs_addch(3), curs_clear(3),  curs_initscr(3),
       curs_scroll(3), curs_refresh(3)
[ Back ]
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