altosui: check for closed serial device before reading

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/ao-tools/altosui/AltosSerial.java b/ao-tools/altosui/AltosSerial.java
index a5566ab898d4f3eb096f2d131e925e585bf8a499..96e8b61f599d2329678dbe547b3edc3eb3389f11 100644 (file)
--- a/ao-tools/altosui/AltosSerial.java
+++ b/ao-tools/altosui/AltosSerial.java
@@ -51,6 +51,8 @@ public class AltosSerial implements Runnable {
 
                try {
                        for (;;) {
 
                try {
                        for (;;) {

+                               if (altos == null)
+                                       break;

                                c = libaltos.altos_getchar(altos, 0);
                                if (Thread.interrupted())
                                        break;
                                c = libaltos.altos_getchar(altos, 0);
                                if (Thread.interrupted())
                                        break;