+ X/Open Curses, Issue 4 describes these functions. It specifies that
+ <STRONG>bkgd</STRONG>, <STRONG>wbkgd</STRONG>, and <STRONG>getbkgd</STRONG> return <STRONG>ERR</STRONG> on failure (in the case of the
+ last, this value is cast to <EM>chtype</EM>), but describes no failure
+ conditions.
+
+ The SVr4.0 manual says that <STRONG>bkgd</STRONG> and <STRONG>wbkgd</STRONG> may return <STRONG>OK</STRONG> "or a non-
+ negative integer if <STRONG>immedok</STRONG> is set", which refers to the return value
+ from <STRONG><A HREF="curs_refresh.3x.html">wrefresh(3x)</A></STRONG>, used to implement the immediate repainting. SVr4
+ <EM>curses</EM>'s <STRONG>wrefresh</STRONG> returns the number of characters written to the
+ screen during the refresh. <EM>ncurses</EM> does not do that.
+
+ Neither X/Open Curses nor the SVr4 manual pages detail how the
+ rendition of characters on the screen updates when <STRONG>bkgd</STRONG> or <STRONG>wbkgd</STRONG>
+ changes the background character. <EM>ncurses</EM>, like SVr4 <EM>curses</EM>, does not
+ (in its non-"wide" configuration) store the background and window
+ attribute contributions to each character cell separately.