Fix recently-introduced crash on double-terminating the Writer thread.

diff --git a/src/lib/writer.cc b/src/lib/writer.cc
index 572a1c3a462d1ffa3f117b6b56378f82ae8435dc..7fd7464885303c5348df3d92b11a87ee9c0ebe65 100644 (file)
--- a/src/lib/writer.cc
+++ b/src/lib/writer.cc
@@ -344,6 +344,10 @@ void
 Writer::terminate_thread (bool can_throw)
 {
        boost::mutex::scoped_lock lock (_mutex);
+       if (_thread == 0) {
+               return;
+       }
+       
        _finish = true;
        _empty_condition.notify_all ();
        _full_condition.notify_all ();