Return std::unique_ptr member as const ref

Returning raw pointer has a risk that it may be stolen by
std::shared_ptr in accident.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/SingletonHolder.h b/src/SingletonHolder.h
index e37cc4ac..19f4e6c9 100644
--- a/src/SingletonHolder.h
+++ b/src/SingletonHolder.h
@@ -50,9 +50,9 @@ private:
 public:
   ~SingletonHolder() {}
 
-  static T* instance()
+  static std::unique_ptr<T>& instance()
   {
-    return instance_.get();
+    return instance_;
   }
 
   static void instance(std::unique_ptr<T> ptr)