#define MgPV(mg,lp) (((lp = (mg)->mg_len) == HEf_SVKEY) ? \
SvPV((SV*)((mg)->mg_ptr),lp) : \
(mg)->mg_ptr)
+
+#define SvTIED_mg(sv,how) \
+ (SvRMAGICAL(sv) ? mg_find((sv),(how)) : Null(MAGIC*))
+#define SvTIED_obj(sv,mg) \
+ ((mg)->mg_obj ? (mg)->mg_obj : sv_2mortal(newRV(sv)))