freebsd-dev/lib/libncurses/curs_outopts.3

.TH curs_outopts 3X ""
.SH NAME
\fBcurs_outopts\fR: \fBclearok\fR, \fBidlok\fR, \fBidcok immedok\fR,
\fBleaveok\fR, \fBsetscrreg\fR, \fBwsetscrreg\fR, \fBscrollok\fR,
\fBnl\fR, \fBnonl\fR - \fBncurses\fR output options
.SH SYNOPSIS
\fB#include <ncurses.h>\fR

\fBint clearok(WINDOW *win, bool bf);\fR
.br
\fBint idlok(WINDOW *win, bool bf);\fR
.br
\fBvoid idcok(WINDOW *win, bool bf);\fR
.br
\fBvoid immedok(WINDOW *win, bool bf);\fR
.br
\fBint leaveok(WINDOW *win, bool bf);\fR
.br
\fBint setscrreg(int top, int bot);\fR
.br
\fBint wsetscrreg(WINDOW *win, int top, int bot);\fR
.br
\fBint scrollok(WINDOW *win, bool bf);\fR
.br
\fBint nl(void);\fR
.br
\fBint nonl(void);\fR
.br
.SH DESCRIPTION
These routines set options that change the style of output within
\fBncurses\fR.  All options are initially \fBFALSE\fR, unless otherwise stated.
It is not necessary to turn these options off before calling \fBendwin\fR.

With the \fBclearok\fR routine, if enabled (\fIbf\fR is \fBTRUE\fR), the next
call to \fBwrefresh\fR 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 \fIwin\fR argument to \fBclearok\fR is the global variable \fBcurscr\fR,
the next call to \fBwrefresh\fR with any window causes the screen to be cleared
and repainted from scratch.

With the \fBidlok\fR routine, if enabled (\fIbf\fR is \fBTRUE\fR),
\fBncurses\fR considers using the hardware insert/delete line feature of
terminals so equipped.  If disabled (\fIbf\fR is \fBFALSE\fR), \fBncurses\fR
very seldom uses this feature.  (The insert/delete character feature is always
considered.)  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 isn't really needed.  If insert/delete line cannot be
used, \fBncurses\fR redraws the changed portions of all lines.

With the \fBidcok\fR routine, if enabled (\fIbf\fR is \fBTRUE\fR),
\fBncurses\fR considers using the hardware insert/delete character feature of
terminals so equipped.  This is enabled by default.

With the \fBimmedok\fR routine, if enabled (\fIbf\fR is \fBTRUE)\fR, any change
in the window image, such as the ones caused by \fBwaddch, wclrtobot, wscrl\fR,
\fIetc\fR., automatically cause a call to \fBwrefresh\fR.  However, it may
degrade the performance considerably, due to repeated calls to \fBwrefresh\fR.
It is disabled by default.

Normally, the hardware cursor is left at the location of the window cursor
being refreshed.  The \fBleaveok\fR 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.  If
possible, the cursor is made invisible when this option is enabled.

The \fBsetscrreg\fR and \fBwsetscrreg\fR routines allow the application
programmer to set a software scrolling region in a window.  \fItop\fR and
\fIbot\fR 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
\fBscrollok\fR are 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 capability in the terminal, like that in the VT100.
If \fBidlok\fR 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 \fBscrollok\fR 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, (\fIbf\fR is \fBFALSE\fR), the cursor is left on the bottom
line.  If enabled, (\fIbf\fR is \fBTRUE\fR), \fBwrefresh\fR is called on the
window, and the physical terminal and window are scrolled up one line.  [Note
that in order to get the physical scrolling effect on the terminal, it is also
necessary to call \fBidlok\fR.]

The \fBnl\fR and \fBnonl\fR routines control whether newline is translated into
carriage return and linefeed on output, and whether return is translated into
newline on input.  Initially, the translations do occur.  By disabling these
translations using \fBnonl\fR, \fBncurses\fR is able to make better use of the
linefeed capability, resulting in faster cursor motion.
.SH RETURN VALUE
\fBsetscrreg\fR and \fBwsetscrreg\fR return \fBOK\fR upon success and \fBERR\fR upon failure.
All other routines that return an integer always return \fBOK\fR.
.SH BUGS
The entry points \fBidcok\fR, \fBimmedok\fR are not yet implemented in
ncurses 1.8.6.  Setting \fIidlok\fR has unfortunate effects on scrolling
windows.
.SH NOTES
Note that \fBclearok\fR, \fBleaveok\fR, \fBscrollok\fR, \fBidcok\fR, \fBnl\fR,
\fBnonl\fR and \fBsetscrreg\fR may be macros.

The \fBimmedok\fR routine is useful for windows that are used as terminal
emulators.
.SH SEE ALSO
\fBncurses\fR(3X), \fBcurs_addch\fR(3X), \fBcurs_clear\fR(3X),
\fBcurs_initscr\fR(3X), \fBcurs_scroll\fR(3X), \fBcurs_refresh\fR(3X)
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