+ if (!(old_attr & A_COLOR)) {
+ old_pair = 0;
+ }
+ T(("... old background char %s, attr %s, pair %d",
+ _tracechar(CharOf(old_char)), _traceattr(old_attr), old_pair));
+
+ new_char = new_bkgd;
+ RemAttr(new_char, ~A_CHARTEXT);
+ new_attr = AttrOf(new_bkgd);
+ new_pair = GetPair(new_bkgd);
+
+ /* SVr4 limits background character to printable 7-bits */
+ if (!Charable(new_bkgd)) {
+ new_char = old_char;
+ }
+ if (!(new_attr & A_COLOR)) {
+ new_pair = 0;
+ }
+ T(("... new background char %s, attr %s, pair %d",
+ _tracechar(CharOf(new_char)), _traceattr(new_attr), new_pair));
+
+ (void) wbkgrndset(win, CHREF(new_bkgd));
+
+ /* SVr4 updates color pair if old/new match, otherwise just attrs */
+ if ((new_pair != 0) && (new_pair == old_pair)) {
+ WINDOW_ATTRS(win) = new_attr;
+ SET_WINDOW_PAIR(win, new_pair);
+ } else {
+ WINDOW_ATTRS(win) = new_attr;
+ }