diff --git a/common/JackConstants.h b/common/JackConstants.h
index 4f538807..96c6b4a2 100644
--- a/common/JackConstants.h
+++ b/common/JackConstants.h
@@ -35,6 +35,7 @@
 #define JACK_CLIENT_NAME_SIZE 64
 #define JACK_MESSAGE_SIZE 256
 #define JACK_UUID_SIZE 36 // to match jack1 and uuid.h
+#define JACK_UUID_STRING_SIZE (JACK_UUID_SIZE+1) /* includes trailing null */
 #define JACK_SESSION_COMMAND_SIZE 256
 
 #define SYNC_MAX_NAME_SIZE 256