diff --git a/examples/osgunittests/osgunittests.cpp b/examples/osgunittests/osgunittests.cpp
index 5640ebbe2..4de89227d 100644
--- a/examples/osgunittests/osgunittests.cpp
+++ b/examples/osgunittests/osgunittests.cpp
@@ -115,6 +115,7 @@ void sizeOfTest()
 
   std::cout<<"sizeof(std::istream::pos_type)=="<<sizeof(std::istream::pos_type)<<std::endl;
   std::cout<<"sizeof(std::istream::off_type)=="<<sizeof(std::istream::off_type)<<std::endl;
+  std::cout<<"sizeof(OpenThreads::Mutex)=="<<sizeof(OpenThreads::Mutex)<<std::endl;
 
 }