better error handling

Makefile

@@ -20,8 +20,8 @@ TARGETS = pixelflut-render pixelflut-bench
 
 all: $(TARGETS)
 
-pixelflut-render: new.c pixelflut.h
-	$(CC) $(STD) $(OPT) -pthread $(WARN) $(EXTRA) -o $@ new.c
+pixelflut-render: pixelflut.c pixelflut.h
+	$(CC) $(STD) $(OPT) -pthread $(WARN) $(EXTRA) -o $@ pixelflut.c
 
 pixelflut-bench: bench.c pixelflut.h
 	$(CC) $(STD) $(OPT) -pthread $(WARN) $(EXTRA) -o $@ bench.c

pixelflut.c

@@ -65,7 +65,7 @@
 #define FRAME_BYTES    (FRAME_PIXELS * FRAME_CHANNELS)
 
 /* Top-left corner where the frame is drawn on the shared wall. */
-#define CANVAS_OFFSET_X 1200
+#define CANVAS_OFFSET_X 80
 #define CANVAS_OFFSET_Y 40
 
 /* Number of datagrams needed to cover a whole frame once. */
@@ -231,15 +231,21 @@ static void *worker_main(void *arg)
 				/* Transient back-pressure. Back off briefly so the queue
 				 * drains (rather than spinning on failing syscalls), then
 				 * resend the same batch - no need to repaint. */
-				usleep(200);
+				usleep(100);
 				continue;
 			case ECONNREFUSED:
 				break; /* stale ICMP on connected UDP; repaint and retry */
+			case EHOSTUNREACH: /* display down / IPv6 ND unresolved */
+			case ENETUNREACH:
+			case EHOSTDOWN:
+			case ENETDOWN:
+				usleep(100000);
+				break;
 			default:
 				perror("sendmmsg");
 				break;
 			}
-			break; /* ECONNREFUSED / unexpected: stop, repaint, retry */
+			break;
 		}
 	}
 

run.sh

@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+./pixelflut-render ix1 2