#define MgTAINTEDDIR_on(mg) (mg->mg_flags |= MGf_TAINTEDDIR)
#define MgTAINTEDDIR_off(mg) (mg->mg_flags &= ~MGf_TAINTEDDIR)
-#define MgPV(mg,lp) (((lp = (mg)->mg_len) == HEf_SVKEY) ? \
+#define MgPV(mg,lp) ((((int)(lp = (mg)->mg_len)) == HEf_SVKEY) ? \
SvPV((SV*)((mg)->mg_ptr),lp) : \
(mg)->mg_ptr)