Fix thinko.

diff --git a/glretrace.py b/glretrace.py
index 8716819..f809b9e 100644 (file)
--- a/glretrace.py
+++ b/glretrace.py
@@ -164,8 +164,8 @@ unsigned __frame = 0;
 long long __startTime = 0;
 bool __wait = false;
 
-const char *__compare_prefix = "";
-const char *__snapshot_prefix = "";
+const char *__compare_prefix = NULL;
+const char *__snapshot_prefix = NULL;
 
 
 static void