U8 xbm_rare; /* rarest character in string */
};
-/* This structure much match XPVCV in cv.h */
+/* This structure must match XPVCV in cv.h */
typedef U16 cv_flags_t;
Guarantees to evaluate sv only once; use the more efficient C<SvPVbyte>
otherwise.
+=for apidoc Am|bool|SvIsCOW|SV* sv
+Returns a boolean indicating whether the SV is Copy-On-Write. (either shared
+hash key scalars, or full Copy On Write scalars if 5.9.0 is configured for
+COW)
+
+=for apidoc Am|bool|SvIsCOW_shared_hash|SV* sv
+Returns a boolean indicating whether the SV is Copy-On-Write shared hash key
+scalar.
=cut
*/