.\" $OpenBSD: curs_bkgd.3,v 1.4 1997/12/03 05:44:54 millert Exp $
.\" Id: curs_bkgd.3x,v 1.10 1996/07/20 23:48:30 tom Exp $
.TH curs_bkgd 3 ""
.
.SH NAME
\fBbkgdset\fR, \fBwbkgdset\fR, \fBbkgd\fR,
\fBwbkgd\fR - \fBcurses\fR window background manipulation routines
.
.SH SYNOPSIS
\fB#include <curses.h>\fR

\fBvoid bkgdset(const chtype ch);\fR
.br
\fBvoid wbkgdset(WINDOW *win, const chtype ch);\fR
.br
\fBint bkgd(const chtype ch);\fR
.br
\fBint wbkgd(WINDOW *win, const chtype ch);\fR
.br
\fBchtype getbkgd(WINDOW *win);\fR
.br
.
.SH DESCRIPTION
The \fBbkgdset\fR and \fBwbkgdset\fR routines manipulate the
background of the named window.
The window background is a \fBchtype\fR consisting of
any combination of attributes (i.e., rendition) and a character.
The attribute part of the background is combined (OR'ed) with all non-blank
characters that are written into the window with \fBwaddch\fR.  Both
the character and attribute parts of the background are combined with
the blank characters.  The background becomes a property of the
character and moves with the character through any scrolling and
insert/delete line/character operations.

To the extent possible on a
particular terminal, the attribute part of the background is displayed
as the graphic rendition of the character put on the screen.

The \fBbkgd\fR and \fBwbkgd\fR functions
set the background property of the current or specified window
and then apply this setting to every character position in that window:

.RS
The rendition of every character on the screen is changed to
the new background rendition.

Wherever the former background character
appears, it is changed to the new background character.
.RE

The \fBgetbkgd\fR function returns the given window's current background
character/attribute pair.
.
.SH RETURN VALUE
The routines \fBbkgd\fR and \fBwbkgd\fR return the integer \fBOK\fR.
The SVr4.0 manual says "or a non-negative integer if \fBimmedok\fR is set",
but this appears to be an error.
.
.SH NOTES
Note that \fBbkgdset\fR and \fBbkgd\fR may be macros.
.
.SH PORTABILITY
These functions are described in the XSI Curses standard, Issue 4.  The draft
does not include \fBconst\fR qualifiers on the arguments.  The standard
specifies that \fBbkgd\fR and \fBwbkgd\fR return \fBERR\fR, on failure. but
gives no failure conditions.
.
.SH SEE ALSO
\fBcurses\fR(3), \fBcurs_addch\fR(3), \fBcurs_outopts\fR(3)
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