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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | PORTABILITY | NOTES | SEE ALSO | COLOPHON |
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curs_outopts(3X) curs_outopts(3X)
clearok, idlok, idcok, immedok, leaveok, setscrreg, wsetscrreg,
scrollok - 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 scrollok(WINDOW *win, bool bf);
int setscrreg(int top, int bot);
int wsetscrreg(WINDOW *win, int top, int bot);
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.)
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.
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.
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.
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. Informa‐
tion 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
[email protected]. This page was obtained from the
project's upstream Git mirror of the CVS repository
⟨https://github.com/mirror/ncurses.git⟩ on 2024-06-14. (At that
time, the date of the most recent commit that was found in the
repository was 2023-03-12.) 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
[email protected]
curs_outopts(3X)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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