diff --git a/cf/check-symbols.sh b/cf/check-symbols.sh
index 0aa2e3cc8..ce2964ba9 100644
--- a/cf/check-symbols.sh
+++ b/cf/check-symbols.sh
@@ -22,7 +22,7 @@ while test $# != 0 ;do
        esym="${esym} print_version\$" ;;
     -asn1compile)
        esym="${esym} copy_ free_ length_ decode_ encode_ length_ "
-       esym="${esym} *.2int\$ int2 .*_units\$" ;;
+       esym="${esym} *.2int\$ int2 asn1_[A-Za-z0-9]*_units\$" ;;
     -*) echo "unknown option $1" ; exit 1 ;;
     *) break ;;
   esac