diff --git a/reactos/include/psdk/winnt.h b/reactos/include/psdk/winnt.h
index 824067dcdeb..bcf70a22029 100644
--- a/reactos/include/psdk/winnt.h
+++ b/reactos/include/psdk/winnt.h
@@ -2210,6 +2210,10 @@ typedef struct _CONTEXT {
 } CONTEXT;
 #elif defined(__x86_64__)
 
+#define UNW_FLAG_NHANDLER  0
+#define UNW_FLAG_EHANDLER  1
+#define UNW_FLAG_UHANDLER  2
+#define UNW_FLAG_CHAININFO 4
 
 #define CONTEXT_AMD64 0x100000