diff --git a/FileWrapper_Lin.cpp b/FileWrapper_Lin.cpp
index 31ced1c..54cfe0a 100644
--- a/FileWrapper_Lin.cpp
+++ b/FileWrapper_Lin.cpp
@@ -13,7 +13,7 @@ struct DirWalk::_impl
     std::string root;
 };
 
-DirWalk::DirWalk(const std::string& DirName)
+DirWalk::DirWalk(const std::string& DirName) : _p(new _impl)
 {
     std::string realname = DirName;
     int sz = realname.size();