diff --git a/piclib/built-in.scm b/piclib/built-in.scm
index 36e2ab29..8221653e 100644
--- a/piclib/built-in.scm
+++ b/piclib/built-in.scm
@@ -1005,14 +1005,23 @@
 
 (export call-with-port)
 
+(define-library (scheme file)
+  (import (scheme base))
+
+  (define (call-with-input-file filename callback)
+    (call-with-port (open-input-file filename) callback))
+
+  (define (call-with-output-file filename callback)
+    (call-with-port (open-output-file filename) callback))
+
+  (export call-with-input-file
+          call-with-output-file))
+
 ;;; include syntax
 
 (import (scheme read)
         (scheme file))
 
-(define (call-with-input-file filename callback)
-  (call-with-port (open-input-file filename) callback))
-
 (define (read-many filename)
   (call-with-input-file filename
     (lambda (port)