diff --git a/src/aig/gia/giaNewBdd.h b/src/aig/gia/giaNewBdd.h
index bf49f9ce0..0335b5338 100644
--- a/src/aig/gia/giaNewBdd.h
+++ b/src/aig/gia/giaNewBdd.h
@@ -7,6 +7,8 @@
 #include <iomanip>
 #include <cmath>
 
+ABC_NAMESPACE_CXX_HEADER_START
+
 namespace NewBdd {
 
   typedef unsigned short     var;
@@ -796,4 +798,6 @@ namespace NewBdd {
 
 }
 
+ABC_NAMESPACE_CXX_HEADER_END
+
 #endif
diff --git a/src/aig/gia/giaNewTt.h b/src/aig/gia/giaNewTt.h
index e1ba9fd7a..aaf5a9de3 100644
--- a/src/aig/gia/giaNewTt.h
+++ b/src/aig/gia/giaNewTt.h
@@ -7,6 +7,8 @@
 #include <vector>
 #include <bitset>
 
+ABC_NAMESPACE_CXX_HEADER_START
+
 namespace NewTt {
 
   typedef int                bvar;
@@ -246,4 +248,6 @@ namespace NewTt {
 
 }
 
+ABC_NAMESPACE_CXX_HEADER_END
+
 #endif
diff --git a/src/aig/gia/giaTransduction.h b/src/aig/gia/giaTransduction.h
index 6b9a112df..76b62477c 100644
--- a/src/aig/gia/giaTransduction.h
+++ b/src/aig/gia/giaTransduction.h
@@ -11,6 +11,8 @@
 
 #include "gia.h"
 
+ABC_NAMESPACE_CXX_HEADER_START
+
 namespace Transduction {
   
 enum PfState {none, cspf, mspf};
@@ -1596,4 +1598,6 @@ public: // Debug and print
 
 }
 
+ABC_NAMESPACE_CXX_HEADER_END
+
 #endif