# define SvRELEASE_IVX(sv) ((void)((SvFLAGS(sv) & (SVf_OOK|SVf_READONLY|SVf_FAKE)) \
&& Perl_sv_release_IVX(aTHX_ sv)))
# define SvIsCOW_normal(sv) (SvIsCOW(sv) && SvLEN(sv))
+
+#define CAN_COW_MASK (SVs_OBJECT|SVs_GMG|SVs_SMG|SVs_RMG|SVf_IOK|SVf_NOK| \
+ SVf_POK|SVf_ROK|SVp_IOK|SVp_NOK|SVp_POK|SVf_FAKE| \
+ SVf_OOK|SVf_BREAK|SVf_READONLY|SVf_AMAGIC)
+#define CAN_COW_FLAGS (SVp_POK|SVf_POK)
+
#else
# define SvRELEASE_IVX(sv) ((void)SvOOK_off(sv))
#endif /* PERL_COPY_ON_WRITE */