Index: rrdtool-1.2.30/src/rrd_format.h
===================================================================
--- rrdtool-1.2.30.orig/src/rrd_format.h
+++ rrdtool-1.2.30/src/rrd_format.h
@@ -22,7 +22,7 @@
 /* #define RRD_VERSION   "0002" */
 /* changed because microsecond precision requires another field */
 #define RRD_VERSION   "0003"
-#define FLOAT_COOKIE  8.642135E130
+#define FLOAT_COOKIE  ((double)8.642135E130)
 
 #include "rrd_nan_inf.h"