extern uschar *string_open_failed(int, const char *, ...) PRINTF_FUNCTION(2,3);
extern const uschar *string_printing2(const uschar *, BOOL);
extern uschar *string_split_message(uschar *);
+extern uschar *string_timediff(struct timeval *);
extern uschar *string_timesince(struct timeval *);
extern uschar *string_unprinting(uschar *);
#ifdef SUPPORT_I18N