diff --git a/src/lib/pio.pl b/src/lib/pio.pl
index db609aa6..f55e4b03 100644
--- a/src/lib/pio.pl
+++ b/src/lib/pio.pl
@@ -4,9 +4,9 @@
 
    Our goal is to encourage the use of definite clause grammars (DCGs)
    for describing strings. The predicates phrase_from_file/[2,3],
-   phrase_to_file/2 and phrase_to_stream/2 let us apply DCGs transparently
-   to files and streams, and therefore decouple side-effects from
-   declarative descriptions.
+   phrase_to_file/[2,3] and phrase_to_stream/2 let us apply DCGs
+   transparently to files and streams, and therefore decouple side-effects
+   from declarative descriptions.
 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 
 :- module(pio, [phrase_from_file/2,
@@ -26,6 +26,7 @@
 :- meta_predicate(phrase_from_file(2, ?)).
 :- meta_predicate(phrase_from_file(2, ?, ?)).
 :- meta_predicate(phrase_to_file(2, ?)).
+:- meta_predicate(phrase_to_file(2, ?, ?)).
 :- meta_predicate(phrase_to_stream(2, ?)).
 
 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -