sync: add support for DECRQM queries for synchronization ref. #179

st.c

@@ -2444,6 +2444,23 @@ csihandle(void)
 			goto unknown;
 		}
 		break;
+	#if SYNC_PATCH
+	case '$': /* DECRQM -- DEC Request Mode (private) */
+		if (csiescseq.mode[1] == 'p' && csiescseq.priv) {
+			switch (csiescseq.arg[0]) {
+			#if SYNC_PATCH
+			case 2026:
+				/* https://gist.github.com/christianparpart/d8a62cc1ab659194337d73e399004036 */
+				ttywrite(su ? "\033[?2026;1$y" : "\033[?2026;2$y", 11, 0);
+				break;
+			#endif // SYNC_PATCH
+			default:
+				goto unknown;
+			}
+			break;
+		}
+		goto unknown;
+	#endif // SYNC_PATCH
 	case 'r': /* DECSTBM -- Set Scrolling Region */
 		if (csiescseq.priv) {
 			goto unknown;