.\"	$NetBSD: curses_scroll.3,v 1.4 2003/04/16 13:35:01 wiz Exp $
.\"
.\" Copyright (c) 2002
.\"	Brett Lymn (blymn@NetBSD.org, brett_lymn@yahoo.com.au)
.\"
.\" This code is donated to the NetBSD Foundation by the Author.
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.\" modification, are permitted provided that the following conditions
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.\"    products derived from this software without specific prior written
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.Dd August 12, 2002
.Dt CURSES_SCROLL 3
.Os
.Sh NAME
.Nm curses_scroll ,
.Nm scrl ,
.Nm wscrl
.Nm scroll ,
.Nm scrollok ,
.Nm setscrreg ,
.Nm wsetscrreg
.Nd curses window scrolling routines
.Sh LIBRARY
.Lb libcurses
.Sh SYNOPSIS
.In curses.h
.Ft int
.Fn scrl "int n"
.Ft int
.Fn wscrl "WINDOW *win" "int n"
.Ft int
.Fn scroll "WINDOW *win"
.Ft int
.Fn scrollok "WINDOW *win" "boolf flag"
.Ft int
.Fn setscrreg "int top" "int bottom"
.Ft int
.Fn wsetscrreg "WINDOW *win" "int top" "int bottom"
.Sh DESCRIPTION
These functions scroll areas on
.Dv stdscr
or on the specified window.
.Pp
The
.Fn scrl
function scrolls
.Dv stdscr
by
.Fa n
lines.
If
.Fa n
is positive then then
.Dv stdscr
is scrolled up.
.Fa n
lines are lost from the top of
.Dv stdscr
and
.Fa n
blank lines are inserted at the bottom.
If
.Fa n
is negative then
.Dv stdscr
is scrolled down.
.Fa n
blank lines are inserted at the top of
.Dv stdscr
and
.Fa n
lines are lost from the bottom.
.Pp
The
.Fn wscrl
function is the same as the
.Fn scrl
function, excepting that it scrolls the window specified by
.Fa win .
.Pp
The
.Fn scroll
function scrolls the window
.Fa win
up by one line.
.Pp
The scrolling behaviour of a window can be controlled by using the
.Fn scrollok
function.
If the
.Fa flag
argument is
.Dv TRUE
then a line wrap at the bottom of the window will cause the window to
be scrolled up one line, if
.Fa flag
is
.Dv FALSE
then lines that would force a scroll will be truncated.
.Pp
The
.Fn setscrreg
function sets up a software scrolling region on
.Dv stdscr
which will define a region of the screen that will be scrolled.
The scrolling of this region is also controlled by the
.Fn scrollok
function.
.Pp
The
.Fn wsetscrreg
function does the same as the
.Fn setscrreg
function, except that the scrolling region is set on the window specified by
.Fa win .
.Pp
If a scrolling region has been set with the
.Fn setscrreg
or
.Fn wsetscrreg
functions and the current cursor position is inside the scrolling region,
then only the area inside the scrolling region is scrolled.
.Sh RETURN VALUES
Functions returning pointers will return
.Dv NULL
if an error is detected.
The functions that return an int will return one of the following
values:
.Pp
.Bl -tag -width ERR -compact
.It Er OK
The function completed successfully.
.It Er ERR
An error occurred in the function.
.El
.Sh SEE ALSO
.Xr curses_deleteln 3 ,
.Xr curses_insdelln 3 ,
.Xr curses_insertln 3
.Sh STANDARDS
The
.Nx
Curses library complies with the X/Open Curses specification, part of the
Single Unix Specification.
.Sh HISTORY
The Curses package appeared in
.Bx 4.0 .