1 files changed, 1 insertions, 1 deletions
diff --git a/proto.h b/proto.h
index bd27c20b60..5222e730b1 100644
--- a/proto.h
+++ b/proto.h
@@ -922,7 +922,7 @@ PERL_CALLCONV char*	Perl_sv_2pvbyte_nolen(pTHX_ SV* sv);
 PERL_CALLCONV char*	Perl_sv_pv(pTHX_ SV *sv);
 PERL_CALLCONV char*	Perl_sv_pvutf8(pTHX_ SV *sv);
 PERL_CALLCONV char*	Perl_sv_pvbyte(pTHX_ SV *sv);
-PERL_CALLCONV void	Perl_sv_utf8_upgrade(pTHX_ SV *sv);
+PERL_CALLCONV STRLEN	Perl_sv_utf8_upgrade(pTHX_ SV *sv);
 PERL_CALLCONV bool	Perl_sv_utf8_downgrade(pTHX_ SV *sv, bool fail_ok);
 PERL_CALLCONV void	Perl_sv_utf8_encode(pTHX_ SV *sv);
 PERL_CALLCONV bool	Perl_sv_utf8_decode(pTHX_ SV *sv);