Fix warning.

diff --git a/src/lib/butler.cc b/src/lib/butler.cc
index 053d7c3bcf16fb1813d77b4a930d1ae3d1f6db9c..910b5ea4897b612c76a458909d112b11185d67dc 100644 (file)
--- a/src/lib/butler.cc
+++ b/src/lib/butler.cc
@@ -65,7 +65,7 @@ Butler::Butler (weak_ptr<const Film> film, shared_ptr<Player> player, AudioMappi
        /* Create some threads to do work on the PlayerVideos we are creating; at present this is used to
           multi-thread JPEG2000 decoding.
        */
-       for (int i = 0; i < boost::thread::hardware_concurrency(); ++i) {
+       for (size_t i = 0; i < boost::thread::hardware_concurrency(); ++i) {
                _prepare_pool.create_thread (bind (&boost::asio::io_service::run, &_prepare_service));
        }
 }