diff --git a/lib/krb5/krb5_rd_error.3 b/lib/krb5/krb5_rd_error.3
index 2cf8eff7b..46c7a135c 100644
--- a/lib/krb5/krb5_rd_error.3
+++ b/lib/krb5/krb5_rd_error.3
@@ -47,7 +47,7 @@ Kerberos 5 Library (libkrb5, -lkrb5)
 .Ft krb5_error_code
 .Fo krb5_rd_error
 .Fa "krb5_context context"
-.Fa "krb5_data *msg"
+.Fa "const krb5_data *msg"
 .Fa "KRB_ERROR *result"
 .Fc
 .Ft void