PERL_CALLCONV IV Perl_utf8_distance(pTHX_ U8 *a, U8 *b);
PERL_CALLCONV U8* Perl_utf8_hop(pTHX_ U8 *s, I32 off);
PERL_CALLCONV U8* Perl_utf8_to_bytes(pTHX_ U8 *s, STRLEN *len);
+PERL_CALLCONV U8* Perl_bytes_from_utf8(pTHX_ U8 *s, STRLEN *len, bool *is_utf8);
PERL_CALLCONV U8* Perl_bytes_to_utf8(pTHX_ U8 *s, STRLEN *len);
PERL_CALLCONV UV Perl_utf8_to_uv_simple(pTHX_ U8 *s, STRLEN* retlen);
PERL_CALLCONV UV Perl_utf8_to_uv(pTHX_ U8 *s, STRLEN curlen, STRLEN* retlen, U32 flags);