PERL_CALLCONV U8* Perl_utf16_to_utf8(pTHX_ U8* p, U8 *d, I32 bytelen, I32 *newlen);
PERL_CALLCONV U8* Perl_utf16_to_utf8_reversed(pTHX_ U8* p, U8 *d, I32 bytelen, I32 *newlen);
PERL_CALLCONV STRLEN Perl_utf8_length(pTHX_ U8* s, U8 *e);
-PERL_CALLCONV I32 Perl_utf8_distance(pTHX_ U8 *a, U8 *b);
+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_to_utf8(pTHX_ U8 *s, STRLEN *len);