.\"***************************************************************************
-.\" Copyright (c) 2002-2006,2010 Free Software Foundation, Inc. *
+.\" Copyright 2018-2020,2021 Thomas E. Dickey *
+.\" Copyright 2002-2015,2017 Free Software Foundation, Inc. *
.\" *
.\" Permission is hereby granted, free of charge, to any person obtaining a *
.\" copy of this software and associated documentation files (the *
.\" authorization. *
.\"***************************************************************************
.\"
-.\" $Id: curs_bkgrnd.3x,v 1.4 2010/12/04 18:49:20 tom Exp $
+.\" $Id: curs_bkgrnd.3x,v 1.14 2021/12/25 21:41:58 tom Exp $
+.de bP
+.ie n .IP \(bu 4
+.el .IP \(bu 2
+..
.TH curs_bkgrnd 3X ""
.SH NAME
-\fBbkgrnd\fR,
-\fBwbkgrnd\fR,
-\fBbkgrndset\fR,
-\fBwbkgrndset\fR,
-\fBgetbkgrnd\fR,
-\fBwgetbkgrnd\fR \- \fBcurses\fR window complex background manipulation routines
+\fBbkgrnd\fP,
+\fBwbkgrnd\fP,
+\fBbkgrndset\fP,
+\fBwbkgrndset\fP,
+\fBgetbkgrnd\fP,
+\fBwgetbkgrnd\fP \- \fBcurses\fP window complex background manipulation routines
.SH SYNOPSIS
.PP
.B #include <curses.h>
.sp
-\fBint bkgrnd(\fR\fB const cchar_t *\fR\fIwch\fR\fB);\fR
+\fBint bkgrnd(\fP\fB const cchar_t *\fP\fIwch\fP\fB);\fP
.br
-\fBint wbkgrnd(\fR\fB WINDOW *\fR\fIwin\fR\fB, const cchar_t *\fR\fIwch\fR\fB);\fR
-.br
-\fBvoid bkgrndset(const cchar_t *\fR\fIwch\fR \fB);\fR
-.br
-\fBvoid wbkgrndset(WINDOW *\fR\fIwin\fR\fB, const cchar_t *\fR\fIwch\fR\fB);\fR
+\fBint wbkgrnd(\fP\fB WINDOW *\fP\fIwin\fP\fB, const cchar_t *\fP\fIwch\fP\fB);\fP
+.sp
+\fBvoid bkgrndset(const cchar_t *\fP\fIwch\fP \fB);\fP
.br
-\fBint getbkgrnd(cchar_t *\fR\fIwch\fR\fB);\fR
+\fBvoid wbkgrndset(WINDOW *\fP\fIwin\fP\fB, const cchar_t *\fP\fIwch\fP\fB);\fP
+.sp
+\fBint getbkgrnd(cchar_t *\fP\fIwch\fP\fB);\fP
.br
-\fBint wgetbkgrnd(WINDOW *\fR\fIwin\fR\fB, cchar_t *\fR\fIwch\fR\fB);\fR
+\fBint wgetbkgrnd(WINDOW *\fP\fIwin\fP\fB, cchar_t *\fP\fIwch\fP\fB);\fP
.br
.SH DESCRIPTION
-The \fBbkgrndset\fR and \fBwbkgrndset\fR routines manipulate the
+.SS bkgrndset
+.PP
+The \fBbkgrndset\fP and \fBwbkgrndset\fP routines manipulate the
background of the named window.
-The window background is a \fBcchar_t\fR consisting of
+The window background is a \fBcchar_t\fP consisting of
any combination of attributes (i.e., rendition) and a complex 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
+characters that are written into the window with \fBwaddch\fP.
+Both
the character and attribute parts of the background are combined with
the blank characters.
The background becomes a property of the
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.
+.SS bkgrnd
.PP
-The \fBbkgrnd\fR and \fBwbkgrnd\fR functions
+The \fBbkgrnd\fP and \fBwbkgrnd\fP functions
set the background property of the current or specified window
and then apply this setting to every character position in that window:
-.RS
-.PP
+.bP
The rendition of every character on the screen is changed to
the new background rendition.
-.PP
+.bP
Wherever the former background character
appears, it is changed to the new background character.
-.RE
+.SS getbkgrnd
.PP
-The \fBgetbkgrnd\fR function returns the given window's current background
-character/attribute pair via the \fBwch\fR pointer.
-.
+The \fBgetbkgrnd\fP function returns the given window's current background
+character/attribute pair via the \fBwch\fP pointer.
+If the given window pointer is null,
+the character is not updated (but no error returned).
.SH NOTES
Note that
-\fBbkgrnd\fR,
-\fBbkgrndset\fR, and
-\fBgetbkgrnd\fR
+\fBbkgrnd\fP,
+\fBbkgrndset\fP, and
+\fBgetbkgrnd\fP
may be macros.
-.SH RETURN VALUES
-The \fBbkgrndset\fR and \fBwbkgrndset\fR routines do not return a value.
.PP
-Upon successful completion, the other functions return \fBOK\fR.
-Otherwise, they return \fBERR\fR.
+X/Open Curses does not provide details on how the rendition is changed.
+This implementation follows the approach used in SVr4 curses,
+which is explained in the manual page for \fBwbkgd\fP.
+.SH RETURN VALUE
+.PP
+The \fBbkgrndset\fP and \fBwbkgrndset\fP routines do not return a value.
+.PP
+Upon successful completion, the other functions return \fBOK\fP.
+Otherwise, they return \fBERR\fP:
+.bP
A null window pointer is treated as an error.
+.bP
+A null character pointer is treated as an error.
+.SH PORTABILITY
+.PP
+These functions are described in the XSI Curses standard, Issue 4
+(X/Open Curses).
.SH SEE ALSO
-\fBcurses\fR(3X),
-\fBcurs_bkgd\fR(3X)
+\fBcurses\fP(3X),
+\fBcurs_bkgd\fP(3X)
projects / ncurses.git / blobdiff