diff --git a/src/backend/utils/adt/float.c b/src/backend/utils/adt/float.c
index ba6abbb247c545f5e261ed276450f4a3e3ccd5e6..46ff93d060034a9b1ed001ab6d5edc5860b05ae5 100644
--- a/src/backend/utils/adt/float.c
+++ b/src/backend/utils/adt/float.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/float.c,v 1.36 1999/01/10 17:13:06 thomas Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/float.c,v 1.37 1999/01/17 03:28:37 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -71,6 +71,10 @@
 #define SHRT_MIN (-32768)
 #endif
 
+#ifndef NAN
+#define NAN		(0.0/0.0)
+#endif
+
 #define FORMAT			'g'		/* use "g" output format as standard
 								 * format */
 /* not sure what the following should be, but better to make it over-sufficient */