curs_outopts(3x) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | PORTABILITY | NOTES | SEE ALSO | COLOPHON

curs_outopts(3X)                                        curs_outopts(3X)

NAME         top

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

SYNOPSIS         top

       #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         top

       These routines set options that change the style of output within
       curses.   All options are initially FALSE, unless otherwise stat‐
       ed.  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 wre‐
       fresh with this window will clear the screen completely  and  re‐
       draw  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  insertion and deletion.  This option should be en‐
       abled only if the application needs insert/delete line, for exam‐
       ple, for a screen editor.  It is disabled by default because  in‐
       sert/delete  line  tends to be visually annoying when used in ap‐
       plications where it is not really needed.  If insert/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 considers using the hardware insert/delete character  fea‐
       ture 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., automatically cause a call to wrefresh.  However, it
       may degrade performance considerably, due to  repeated  calls  to
       wrefresh.  It is disabled by default.

   leaveok
       Normally, the hardware cursor is left at the location of the win‐
       dow 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.

   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 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  neces‐
       sary to call idlok).

   setscrreg/wsetscrreg
       The  setscrreg and wsetscrreg routines allow the application pro‐
       grammer 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  capa‐
       bility  in the terminal, like that in the VT100.  If idlok is en‐
       abled and the terminal has  either  a  scrolling  region  or  in‐
       sert/delete  line  capability,  they will probably be used by the
       output routines.)

RETURN VALUE         top

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

       X/Open Curses does not define any error conditions.

       In this implementation,

       •   those functions that have a window pointer will return an er‐
           ror if the window pointer is null

       •   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.

PORTABILITY         top

       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 in‐
       put.  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 inter‐
       feres with output optimization, nl/nonl were amended after ncurs‐
       es 6.2 to eliminate their effect on output.

       Some historic curses implementations had, as an undocumented fea‐
       ture, the ability to do the equivalent of clearok(..., 1) by say‐
       ing 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 al‐
       so forced a physical refresh.  XSI Curses does not require this,
       and ncurses avoids doing it to perform better vertical-motion op‐
       timization 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 docu‐
       mentation does this, but the code does not.  Use curs_set to make
       the cursor invisible.

NOTES         top

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

       The immedok routine is useful for windows that are used as termi‐
       nal emulators.

SEE ALSO         top

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

COLOPHON         top

       This page is part of the ncurses (new curses) project.  Informa‐
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       ⟨https://github.com/mirror/ncurses.git⟩ on 2024-06-14.  (At that
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                                                        curs_outopts(3X)