.\"	$NetBSD: curses_touch.3,v 1.10 2018/02/08 09:05:16 dholland Exp $
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.\" Copyright (c) 2002
.\"	Brett Lymn (blymn@NetBSD.org, brett_lymn@yahoo.com.au)
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.Dd January 2, 2017
.Dt CURSES_TOUCH 3
.Os
.Sh NAME
.Nm curses_touch ,
.Nm touchline ,
.Nm touchoverlap ,
.Nm touchwin ,
.Nm untouchwin ,
.Nm wtouchln ,
.Nm is_linetouched ,
.Nm is_wintouched ,
.Nm redrawwin ,
.Nm wredrawln ,
.Nm syncok ,
.Nm wsyncup ,
.Nm wsyncdown
.Nd curses window modification routines
.Sh LIBRARY
.Lb libcurses
.Sh SYNOPSIS
.In curses.h
.Ft int
.Fn touchline "WINDOW *win" "int start" "int count"
.Ft int
.Fn touchoverlap "WINDOW *win1" "WINDOW *win2"
.Ft int
.Fn touchwin "WINDOW *win"
.Ft int
.Fn untouchwin "WINDOW *win"
.Ft int
.Fn wtouchln "WINDOW *win" "int line" "int n" "boolf changed"
.Ft bool
.Fn is_linetouched "WINDOW *win" "int line"
.Ft bool
.Fn is_wintouched "WINDOW *win"
.Ft int
.Fn redrawwin "WINDOW *win"
.Ft int
.Fn wredrawln "WINDOW *win" "int line" "int n"
.Ft int
.Fn syncok "WINDOW *win"
.Ft void
.Fn wsyncup "WINDOW *win"
.Ft void
.Fn wsyncdown "WINDOW *win"
.Sh DESCRIPTION
These functions mark lines and windows as modified and check the modification
status of lines and windows.
.Pp
The
.Fn touchline
function marks
.Fa count
lines starting from
.Fa start
in window
.Fa win
as having been modified.
These characters will be synced to the terminal on the next call to
.Fn wrefresh .
.Pp
The
.Fn touchoverlap
function marks the portion of
.Fa win2
that overlaps
.Fa win1
as being modified.
.Pp
The
.Fn touchwin
function marks the entire window
.Fa win
as having been modified.
Conversely,
the
.Fn untouchwin
function marks the window
.Fa win
as being unmodified, so that any changes made to that window will
not be synced to the terminal during a
.Fn wrefresh .
.Pp
The
.Fn wtouchln
function performs one of two operations on
.Fa n
lines starting at
.Fa line
in the given window.
If
.Fa changed
is 1 then the given line range is marked as being modified, if
.Fa changed
is 0 then the given line range is set to being unmodified.
.Pp
The
.Fn is_linetouched
function returns
.Dv TRUE
if
.Fa line
in window
.Fa win
has been modified since the last refresh was done, otherwise
.Dv FALSE
is returned.
.Pp
.Fn is_wintouched
returns
.Dv TRUE
if the window
.Fa win
has been modified since the last refresh, otherwise
.Dv FALSE
is returned.
.Pp
The
.Fn redrawwin
function marks the entire window
.Fa win
as having been corrupted.
Is is equivalent to the
.Fn touchwin
function.
.Pp
The
.Fn wredrawln
function marks
.Fa n
lines starting at
.Fa line
in the given window as corrupted.
It is equivalent to
.Fn wtouchln win line n 1 .
.Pp
The
.Fn syncok
function determines whether all the ancestors of the specified window are
implicitly touched whenever there is a change in the window.
The initial state is
.Dv FALSE .
.Pp
The
.Fn wsyncup
function touches all ancestors of
.Fa win .
.Pp
The
.Fn wsyncdown
function touches
.Fa win
if any of its ancestors is touched.
.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_refresh 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 .