Return success on libwebsocket_write==0.

src/loop.c

@@ -74,7 +74,7 @@ int mosquitto_main_loop(struct mosquitto_db *db, int *listensock, int listensock
 	int rc;
 #endif
 #ifdef WITH_WEBSOCKETS
-	struct libwebsocket_context *ws_context;
+	struct libwebsocket_context *ws_context = NULL;
 #endif
 
 #ifndef WIN32

src/websockets.c

@@ -151,6 +151,9 @@ static int callback_mqtt(struct libwebsocket_context *context,
 					packet->pos += LWS_SEND_BUFFER_PRE_PADDING;
 				}
 				count = libwebsocket_write(wsi, &packet->payload[packet->pos], packet->to_process, LWS_WRITE_BINARY);
+				if(count < 0){
+					return 0;
+				}
 				packet->to_process -= count;
 				packet->pos += count;
 				if(packet->to_process > 0){