diff --git a/trunk/c5/ida.cpp b/trunk/c5/ida.cpp
index c0655b40..92e24991 100644
--- a/trunk/c5/ida.cpp
+++ b/trunk/c5/ida.cpp
@@ -6,6 +6,7 @@
 #include "algebra.h"
 #include "gf2_32.h"
 #include "polynomi.h"
+#include <functional>
 
 #include "polynomi.cpp"
 
diff --git a/trunk/c5/pssr.cpp b/trunk/c5/pssr.cpp
index c2b21157..a4497059 100644
--- a/trunk/c5/pssr.cpp
+++ b/trunk/c5/pssr.cpp
@@ -2,6 +2,7 @@
 
 #include "pch.h"
 #include "pssr.h"
+#include <functional>
 
 NAMESPACE_BEGIN(CryptoPP)