+static bool
+uses_SGR_39_49(const char *value)
+{
+ return (strstr(value, "39;49") != 0
+ || strstr(value, "49;39") != 0);
+}
+
+/*
+ * Check consistency of termcap extensions related to "screen".
+ */
+static void
+check_screen(TERMTYPE *tp)
+{
+#if NCURSES_XNAMES
+ if (_nc_user_definable) {
+ int have_XT = tigetflag("XT");
+ int have_XM = tigetflag("XM");
+ int have_bce = back_color_erase;
+ bool have_kmouse = FALSE;
+ bool use_sgr_39_49 = FALSE;
+ char *name = _nc_first_name(tp->term_names);
+
+ if (!VALID_BOOLEAN(have_bce)) {
+ have_bce = FALSE;
+ }
+ if (!VALID_BOOLEAN(have_XM)) {
+ have_XM = FALSE;
+ }
+ if (!VALID_BOOLEAN(have_XT)) {
+ have_XT = FALSE;
+ }
+ if (VALID_STRING(key_mouse)) {
+ have_kmouse = !strcmp("\033[M", key_mouse);
+ }
+ if (VALID_STRING(orig_colors)) {
+ use_sgr_39_49 = uses_SGR_39_49(orig_colors);
+ } else if (VALID_STRING(orig_pair)) {
+ use_sgr_39_49 = uses_SGR_39_49(orig_pair);
+ }
+
+ if (have_XM && have_XT) {
+ _nc_warning("Screen's XT capability conflicts with XM");
+ } else if (have_XT
+ && strstr(name, "screen") != 0
+ && strchr(name, '.') != 0) {
+ _nc_warning("Screen's \"screen\" entries should not have XT set");
+ } else if (have_XT) {
+ if (!have_kmouse && have_bce) {
+ if (VALID_STRING(key_mouse)) {
+ _nc_warning("Value of kmous inconsistent with screen's usage");
+ } else {
+ _nc_warning("Expected kmous capability with XT");
+ }
+ }
+ if (!have_bce && max_colors > 0)
+ _nc_warning("Expected bce capability with XT");
+ if (!use_sgr_39_49 && have_bce && max_colors > 0)
+ _nc_warning("Expected orig_colors capability with XT to have 39/49 parameters");
+ if (VALID_STRING(to_status_line))
+ _nc_warning("\"tsl\" capability is redundant, given XT");
+ } else {
+ if (have_kmouse && !have_XM)
+ _nc_warning("Expected XT to be set, given kmous");
+ }
+ }
+#endif
+}
+