curs_outopts(3x) — Linux manual page


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
       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

       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 routines.)

RETURN VALUE         top

       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,

       •   those functions that have a window pointer will return an
           error 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

       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         top

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

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

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