diff --git a/libsrc/general/archive_base.hpp b/libsrc/general/archive_base.hpp
index 7aa7c4b4..f6e18cea 100644
--- a/libsrc/general/archive_base.hpp
+++ b/libsrc/general/archive_base.hpp
@@ -12,6 +12,8 @@ namespace ngstd
 
     virtual Archive & operator & (double & d) = 0;
     virtual Archive & operator & (int & i) = 0;
+    virtual Archive & operator & (long & i) = 0;
+    virtual Archive & operator & (size_t & i) = 0;
     virtual Archive & operator & (short & i) = 0;
     virtual Archive & operator & (unsigned char & i) = 0;
     virtual Archive & operator & (bool & b) = 0;