diff --git a/src/system/FileDescriptor.hxx b/src/system/FileDescriptor.hxx
index faec76319..3b6b0e59a 100644
--- a/src/system/FileDescriptor.hxx
+++ b/src/system/FileDescriptor.hxx
@@ -50,7 +50,8 @@
 /**
  * An OO wrapper for a UNIX file descriptor.
  *
- * This class is unmanaged and trivial.
+ * This class is unmanaged and trivial; for a managed version, see
+ * #UniqueFileDescriptor.
  */
 class FileDescriptor {
 protected: