diff --git a/src/hdf5_array.hpp b/src/hdf5_array.hpp
index 711c0bc..11762bb 100644
--- a/src/hdf5_array.hpp
+++ b/src/hdf5_array.hpp
@@ -263,6 +263,35 @@ namespace CosmoTool {
     }
   };
 
+  struct CosmoString { 
+     char const * s;
+     operator char const *() { return s; }
+     char const *operator=(char const *s0) {
+       s = s0;
+       return s0;
+     }
+  };
+
+  class hdf5_CosmoStringType {
+  public:
+    H5::StrType type;
+
+    hdf5_CosmoStringType() : type(H5::PredType::C_S1, H5T_VARIABLE) {
+    }
+
+    static const hdf5_CosmoStringType *ctype()
+    {
+      static hdf5_CosmoStringType singleton;
+      return &singleton;
+    }
+  };
+
+  template<> struct get_hdf5_data_type<CosmoString> {
+    static H5::DataType type() {
+      return hdf5_CosmoStringType::ctype()->type;
+    }
+  };
+
   template<typename ArrayType>
   void hdf5_write_array(H5_CommonFileGroup& fg, const std::string& data_set_name, const ArrayType& data )
   {