Section: Miscellaneous Library Functions (3X)
window background manipulation routines
void bkgdset(chtype ch);
void wbkgdset(WINDOW *win, chtype ch);
int bkgd(chtype ch);
int wbkgd(WINDOW *win, chtype ch);
chtype getbkgd(WINDOW *win);
routines manipulate the
background of the named window.
The window background is a chtype
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 waddch
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 bkgd and wbkgd functions
set the background property of the current or specified window
and then apply this setting to every character position in that window:
.IP • 4
The rendition of every character on the screen is changed to
the new background rendition.
.IP • 4
Wherever the former background character
appears, it is changed to the new background character.
The getbkgd function returns the given window's current background
The routines bkgd and wbkgd return the integer OK.
The SVr4.0 manual says "or a non-negative integer if immedok is set",
but this appears to be an error.
Note that bkgdset and bkgd may be macros.
These functions are described in the XSI Curses standard, Issue 4.
It specifies that bkgd and wbkgd return ERR on failure,
but gives no failure conditions.