diff --git a/sv.c b/sv.c
index cdea471df7dc..91b64d528cef 100644
--- a/sv.c
+++ b/sv.c
@@ -9961,7 +9961,7 @@ Creates a new SV boolean.
 */
 
 SV *
-Perl_newSVbool(pTHX_ bool bool_val)
+Perl_newSVbool(pTHX_ const bool bool_val)
 {
     PERL_ARGS_ASSERT_NEWSVBOOL;
     SV *sv = newSVsv(bool_val ? &PL_sv_yes : &PL_sv_no);