diff --git a/src/cryptoki.hxx b/src/cryptoki.hxx
index 0e6d351..846f699 100644
--- a/src/cryptoki.hxx
+++ b/src/cryptoki.hxx
@@ -879,16 +879,10 @@ namespace cryptoki {
         CRYPTOLOG("ID="<<_slot);
       }
 
-    private:
-      
-      /// Slots are created from Library::slotList.
-      Slot(const Library& lib, CK_SLOT_ID slot):
-          _library(lib), _slot(slot), _res(CKR_OK) {
-        CRYPTOLOG("ID="<<_slot);
-      }
-
       /// Slots are created from Library::slotList.
-      /** Empty constructor needs immediate assignment. */
+      /** @note Empty constructor needs immediate assignment. This
+          constructor is public only to be inserted to STL
+          containers. */
       Slot(): _slot(0), _res(-1) {
         CRYPTOLOG("ID="<<_slot);
       }
@@ -901,6 +895,14 @@ namespace cryptoki {
         return *this;
       }
 
+    private:
+      
+      /// Slots are created from Library::slotList.
+      Slot(const Library& lib, CK_SLOT_ID slot):
+          _library(lib), _slot(slot), _res(CKR_OK) {
+        CRYPTOLOG("ID="<<_slot);
+      }
+
       bool check(CK_RV result, const std::string& context="") {
         _res = result;
         if (_library.exc() && !*this) {