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curs_outopts 3x



curs_outopts(3x)                                       curs_outopts(3x)




NAME

       clearok, idlok, idcok, immedok, leaveok, setscrreg,
       wsetscrreg, scrollok, nl, 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(void);
       int nonl(void);


DESCRIPTION

       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  op-
       tions off before calling endwin.

       If  clearok is called with TRUE as argument, the next call
       to wrefresh with this window will clear  the  screen  com-
       pletely  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 edi-
       tor.  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 can-
       not  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 char-
       acter 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 inser-
       tion and deletion.

       If  immedok is called with TRUE as argument, any change in
       the window image, such as the ones caused by waddch, wclr-
       tobot,  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 de-
       fault.

       Normally, the hardware cursor is left at the  location  of
       the window cursor being refreshed.  The leaveok option al-
       lows 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 setscrreg and wsetscrreg routines allow  the  applica-
       tion  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 bot-
       tom 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 re-
       gion 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 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('\n')
       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 bet-
       ter use of the line-feed capability, resulting  in  faster
       cursor  motion.   Also, curses will then be able to detect
       the return key.


RETURN VALUE

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

       X/Open does not define any error conditions.

       In this implementation, those functions that have a window
       pointer  will  return  an  error  if the window pointer is
       null.

              wclrtoeol
                   returns an error if  the  cursor  position  is
                   about to wrap.

              wsetscrreg
                   returns  an error if the scrolling region lim-
                   its extend outside the window.

       X/Open does not define any error conditions.  This  imple-
       mentation returns an error if the window pointer is null.


PORTABILITY

       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 con-
       trolled 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 will not alter.

       Some historic curses implementations had,  as  an  undocu-
       mented  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  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 invisible.


NOTES

       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

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



                                                       curs_outopts(3x)

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