curs_outopts(3X) curs_outopts(3X)
NAME
clearok, idlok, idcok, immedok, leaveok, setscrreg, wsetscrreg, scrollok, nl, nonl - 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 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);
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.
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 in-sert/delete insert/delete
sert/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 isn't really needed. If in-sert/delete insert/delete
sert/delete line cannot be used, curses redraws the changed portions of all lines.
If idcok is called with FALSE as second argument, curses no longer considers using the hardware in-sert/delete insert/delete
sert/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 dele-tion. deletion.
tion.
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 setscrreg and wsetscrreg routines allow the application programmer to set a software scrolling
region in a window. top and bot 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.)
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 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). Ini-tially, Initially,
tially, 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.
RETURN VALUE
The functions setscrreg and wsetscrreg return OK upon success and ERR upon failure. All other rou-tines routines
tines that return an integer always return OK.
X/Open 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.
PORTABILITY
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 trans-lations translations
lations 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 equiva-lent equivalent
lent of clearok(..., 1) by saying touchwin(stdscr) or clear(stdscr). This will not work under ncurs-es. ncurses.
es.
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 cur-sor cursor
sor invisible.
NOTES
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.
SEE ALSO
curses(3X), curs_addch(3X), curs_clear(3X), curs_initscr(3X), curs_scroll(3X), curs_refresh(3X)
curs_outopts(3X)
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