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curs_outopts(3)                                                curs_outopts(3)




NAME

       clearok, idlok, idcok, immedok, leaveok, setscrreg, wsetscrreg, scrollok
       - 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 scrollok(WINDOW *win, bool bf);

       int setscrreg(int top, int bot);
       int wsetscrreg(WINDOW *win, int top, int bot);


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 options off before calling endwin(3X).

   clearok
       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.

   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 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.

   idcok
       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.

   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 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.

   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 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 routines.)


RETURN VALUE

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

       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.


PORTABILITY

       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 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, 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(3)

ncurses 6.4 - Generated Thu Jan 5 10:05:46 CST 2023
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