curs_outopts(3)curs_outopts(3)NAME
curs_outopts, clearok, idcok, idlok, immedok, leaveok, nl, nonl,
setscrreg, wsetscrreg, scrollok - Routines for controlling output
options for a Curses terminal
SYNOPSIS
#include <curses.h>
int clearok(
WINDOW *win,
bool bf ); void idcok(
WINDOW *win,
bool bf ); int idlok(
WINDOW *win,
bool bf ); void immedok(
WINDOW *win,
bool bf ); int leaveok(
WINDOW *win,
bool bf ); int nl(
void ); int nonl(
void ); int setscrreg(
int top,
int bot ); int wsetscrreg(
WINDOW *win,
int top,
int bot ); int scrollok(
WINDOW *win,
bool bf );
LIBRARY
Curses Library (libcurses)
STANDARDS
Interfaces documented on this reference page conform to industry stan‐
dards as follows:
clearok, idcok, idlok, immedok, leaveok, nl, nonl, setscrreg, wsetscr‐
reg: XCURSES4.2
Refer to the standards(5) reference page for more information about
industry standards and associated tags.
DESCRIPTION
These routines set options that deal with output within Curses. Unless
stated otherwise, all options are initially FALSE. It is not necessary
to turn these options off before calling endwin.
The clearok routine enables and disables the clearok option. If this
option is enabled (bf is set to TRUE), the next call to wrefresh with
this window clears the screen completely and redraws the entire screen
from scratch. This is useful when the contents of the screen are uncer‐
tain 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.
The idlok routine enables and disables the idlok option. If this option
is enabled (bf is set to TRUE), Curses considers using the hardware
insert/delete line feature if the terminal is so equipped. If the idlok
is disabled (bf is set to FALSE), Curses very seldom uses this hardware
feature. (The insert/delete character feature is always considered.)
This option should be enabled only if the application needs the
insert/delete line feature, for example, for a screen editor. The
option is disabled by default because insert/delete line tends to be
visually annoying when used in applications where it is not needed. If
the insert/delete line feature cannot be used, Curses redraws the
changed portions of all lines.
The idcok routine enables and disables the idcok option. If this option
is enabled (bf is set to TRUE), Curses considers using the hardware
insert/delete character feature if the terminal is so equipped. The
idcok option is enabled by default.
The immedok routine enables and disables the immedok option. If this
option is enabled (bf is set to TRUE), any change in the window image,
such as the ones caused by waddch, wclrtobot, wscrl, and similar rou‐
tines, automatically causes a call to wrefresh. Enabling the immedok
option may degrade performance considerably due to repeated calls to
wrefresh. The option is disabled by default.
The leaveok routine enables and disables the leaveok option. Usually,
the hardware cursor is left at the location of the cursor in the window
being refreshed. When the leaveok option is enabled, the cursor is left
wherever the update happens to leave it. Because this option reduces
the need for cursor motions, it is useful for applications that do not
use the cursor. If possible, Curses makes the cursor invisible when
leaveok is enabled.
The setscrreg and wsetscrreg routines 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 a scrolling region is set and scrollok is enabled, an
attempt to move off the bottom margin line causes all lines in the
scrolling region to scroll up one line. Only the text of the window is
scrolled. (Note that this has nothing to do with the use of a physical
scrolling region in a terminal, such as the VT100. If the idlok option
is enabled and the terminal has either a scrolling region or an
insert/delete line capability, then the output routines will probably
use one of these.)
The scrollok routine enables and disables the scrollok option. This
option controls what happens when the window cursor 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 the scrollok option is disabled, (bf is set to FALSE), the
cursor is left on the bottom line. If the option is enabled, (bf is set
to TRUE), Curses calls wrefresh on the window, and the physical termi‐
nal and window are scrolled up one line. (Note that in order to get
the physical scrolling effect on the terminal, applications must also
call idlok.)
The nl and nonl routines control whether the newline character is
translated into carriage return and linefeed on output, and whether
carriage return is translated into newline on input. By default, the
translations do occur. When the application disables these translations
by using nonl, curses is able to make better use of the linefeed capa‐
bility, resulting in faster cursor motion.
NOTES
The header file <curses.h> automatically includes the header file
<stdio.h>.
Note that nl, nonl and setscrreg may be macros.
The immedok routine is useful for windows that are created as terminal
emulators.
RETURN VALUES
The nl, nonl, setscrreg, and wsetscrreg routines return OK upon success
and ERR upon failure. All other routines that return an integer always
return OK.
SEE ALSO
Functions: curses(3), curs_addch(3), curs_clear(3), curs_initscr(3),
curs_refresh(3), curs_scroll(3)
Others: standards(5)curs_outopts(3)
