.\"	$NetBSD: curses_background.3,v 1.7 2018/09/29 11:23:18 kamil Exp $
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.\" by Julian Coleman.
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.Dd September 29, 2018
.Dt CURSES_BACKGROUND 3
.Os
.Sh NAME
.Nm curses_background ,
.Nm bkgd ,
.Nm bkgdset ,
.Nm getbkgd ,
.Nm wbkgd ,
.Nm wbkgdset
.Nd curses attribute manipulation routines
.Sh LIBRARY
.Lb libcurses
.Sh SYNOPSIS
.In curses.h
.Ft int
.Fn bkgd chtype
.Ft void
.Fn bkgdset chtype
.Ft chtype
.Fn getbkgd "WINDOW *"
.Ft int
.Fn wbkgd "WINDOW *" chtype
.Ft void
.Fn wbkgdset "WINDOW *" chtype
.Sh DESCRIPTION
These functions manipulate the background attributes on
.Dv stdscr
or on the specified window.
.Pp
The function
.Fn wbkgdset win ch
sets the background attributes of the specified window
.Fa win
to
.Fa ch .
.Pp
When the background attributes are set on a window, characters are added to
the window with the logical
.Em OR
of the background attributes and the character's attributes.
If both the background attribute and the character attribute contain color,
the color of the character attribute is rendered.
If the background attribute contains a non-space character, then this
character is added where the foreground character is a space character.
.Pp
Note that subwindows created from
.Fa win
inherit the background attributes of
.Fa win .
.Pp
The function
.Fn wbkgd win ch
sets the background attributes of the specified window
.Fa win
to
.Fa ch
and also sets the rendition of every character position on that window,
as if the characters had been newly added to
.Fa win .
The rendition of characters on subwindows of
.Fa win
is also set to
.Fa ch .
.Pp
The functions
.Fn bkgdset ch
and
.Fn bkgd ch
are equivalent to
.Fn wbkgdset stdscr ch
and
.Fn wbkgd stdscr ch ,
respectively.
.Pp
The function
.Fn getbkgd win
returns the background attributes for the window
.Fa win .
.Sh RETURN VALUES
The functions
.Fn wbkgdset
and
.Fn wbkgd
return OK on success and ERR on failure.
.Sh SEE ALSO
.Xr curses_attributes 3 ,
.Xr curses_color 3 ,
.Xr curses_window 3
.Sh STANDARDS
The
.Nx
Curses library complies with the X/Open Curses specification, part of the
Single Unix Specification.
.Sh HISTORY
These functions first appeared in
.Nx 1.6 .