diff --git a/src/usinstances.cpp b/src/usinstances.cpp
index d9f600dc..e633659e 100644
--- a/src/usinstances.cpp
+++ b/src/usinstances.cpp
@@ -25,6 +25,8 @@
 
 #ifdef _DLL_CPPLIB
 #include <boost/detail/workaround.hpp>
+#include <memory>
+#include <string>
 //
 // This is a horrible workaround, without declaring these symbols extern we get
 // duplicate symbol errors when linking if the application is built without
diff --git a/src/wc_regex_traits.cpp b/src/wc_regex_traits.cpp
index 29a77e15..aee2da18 100644
--- a/src/wc_regex_traits.cpp
+++ b/src/wc_regex_traits.cpp
@@ -23,6 +23,8 @@
 #include <boost/detail/workaround.hpp>
 
 #ifdef _DLL_CPPLIB
+#include <memory>
+#include <string>
 //
 // This is a horrible workaround, without declaring these symbols extern we get
 // duplicate symbol errors when linking if the application is built without