diff --git a/src/trealla b/src/trealla
index 7917680..c91cf8c 160000
--- a/src/trealla
+++ b/src/trealla
@@ -1 +1 @@
-Subproject commit 79176802554b869d45b1a8aea38a2651c3dded52
+Subproject commit c91cf8c4bce299c641cc2b127bb69e5679a82543
diff --git a/trealla/example_test.go b/trealla/example_test.go
index d894875..7b85acc 100644
--- a/trealla/example_test.go
+++ b/trealla/example_test.go
@@ -19,7 +19,7 @@ func Example() {
 	}
 
 	// start a new query
-	query := pl.Query(ctx, "member(X, [1, foo(bar), c]).")
+	query := pl.Query(ctx, "use_module(library(lists)), member(X, [1, foo(bar), c]).")
 	// calling Close is not necessary if you iterate through the whole query, but it doesn't hurt
 	defer query.Close()
 
diff --git a/trealla/interop.go b/trealla/interop.go
index 5347da0..920e48f 100644
--- a/trealla/interop.go
+++ b/trealla/interop.go
@@ -52,7 +52,7 @@ func (pl *prolog) register(ctx context.Context, name string, arity int, proc Pre
 	pl.procs[pi.String()] = proc
 	vars := numbervars(arity)
 	head := functor.Of(vars...)
-	body := Atom("host_rpc").Of(head)
+	body := Atom(":").Of(Atom("wasm_generic"), Atom("host_rpc").Of(head))
 	clause := fmt.Sprintf(`%s :- %s.`, head.String(), body.String())
 	return pl.consultText(ctx, "user", clause)
 }
diff --git a/trealla/libtpl.wasm b/trealla/libtpl.wasm
index 86bb64c..8c819bf 100755
Binary files a/trealla/libtpl.wasm and b/trealla/libtpl.wasm differ
diff --git a/trealla/prolog.go b/trealla/prolog.go
index 91025de..8fce3ed 100644
--- a/trealla/prolog.go
+++ b/trealla/prolog.go
@@ -53,9 +53,11 @@ type prolog struct {
 	spawning map[uint32]*query
 	limiter  chan struct{}
 
-	ptr              uint32
-	realloc          wasmFunc
-	free             wasmFunc
+	ptr uint32
+	// from stdlib
+	realloc wasmFunc
+	free    wasmFunc
+	// from trealla.h
 	pl_consult       wasmFunc
 	pl_capture       wasmFunc
 	pl_capture_read  wasmFunc
@@ -63,6 +65,7 @@ type prolog struct {
 	pl_query         wasmFunc
 	pl_redo          wasmFunc
 	pl_done          wasmFunc
+	pl_error         wasmFunc
 
 	procs map[string]Predicate
 	coros map[int64]coroutine
@@ -104,7 +107,7 @@ func New(opts ...Option) (Prolog, error) {
 }
 
 func (pl *prolog) argv() []string {
-	args := []string{"tpl", "-g", "halt", "--ns"}
+	args := []string{"tpl", "--ns"}
 	if pl.library != "" {
 		args = append(args, "--library", pl.library)
 	}
@@ -130,6 +133,7 @@ func (pl *prolog) init(parent *prolog) error {
 	cfg := wazero.NewModuleConfig().WithName("").WithArgs(argv...).WithFSConfig(fs).
 		WithSysWalltime().WithSysNanotime().WithSysNanosleep().
 		WithOsyield(runtime.Gosched).
+		// WithStdout(os.Stdout).WithStderr(os.Stderr). // for debugging output capture
 		WithRandSource(rand.Reader)
 
 	// run once to initialize global interpreter
@@ -190,6 +194,11 @@ func (pl *prolog) init(parent *prolog) error {
 		return err
 	}
 
+	pl.pl_error, err = pl.function("pl_error")
+	if err != nil {
+		return err
+	}
+
 	pl.pl_consult, err = pl.function("pl_consult")
 	if err != nil {
 		return err
diff --git a/trealla/query.go b/trealla/query.go
index f2430a0..c24b0be 100644
--- a/trealla/query.go
+++ b/trealla/query.go
@@ -511,7 +511,7 @@ func (q *query) Err() error {
 
 func escapeQuery(query string) string {
 	query = queryEscaper.Replace(query)
-	return fmt.Sprintf(`js_ask(%s).`, escapeString(query))
+	return fmt.Sprintf(`wasm:js_ask(%s).`, escapeString(query))
 }
 
 // QueryOption is an optional parameter for queries.