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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | PORTABILITY | NOTES | SEE ALSO | COLOPHON |
curs_outopts(3X) curs_outopts(3X)
clearok, idlok, idcok, immedok, leaveok, setscrreg, wsetscrreg,
scrollok, nl, nonl - curses output options
#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);
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.
setscrreg
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.)
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).
nl, nonl
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 better
use of the line-feed capability, resulting in faster cursor motion.
Also, curses will then be able to detect the return key.
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.
wclrtoeol
returns an error if the cursor position is about to wrap.
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.
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 will not alter.
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.
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.
curses(3X), curs_addch(3X), curs_clear(3X), curs_initscr(3X),
curs_scroll(3X), curs_refresh(3X), curs_variables(3X).
This page is part of the ncurses (new curses) project. Information
about the project can be found at
⟨https://www.gnu.org/software/ncurses/ncurses.html⟩. If you have a
bug report for this manual page, send it to
bug-ncurses-request@gnu.org. This page was obtained from the
project's upstream Git mirror of the CVS repository
⟨git://ncurses.scripts.mit.edu/ncurses.git⟩ on 2017-07-05. If you
discover any rendering problems in this HTML version of the page, or
you believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a mail
to man-pages@man7.org
curs_outopts(3X)