univ.i:

  If HAVE_purify is defined, define UNIV_SET_MEM_TO_ZERO to eliminate Purify warnings

innobase/include/univ.i

@@ -100,6 +100,15 @@ memory is read outside the allocated blocks. */
 
 #define YYDEBUG			1
 
+#ifdef HAVE_purify
+/* The following sets all new allocated memory to zero before use:
+this can be used to eliminate unnecessary Purify warnings, but note that
+it also masks many bugs Purify could detect. For detailed Purify analysis it
+is best to remove the define below and look through the warnings one
+by one. */
+#define UNIV_SET_MEM_TO_ZERO
+#endif
+
 /*
 #define UNIV_SQL_DEBUG
 #define UNIV_LOG_DEBUG