Index: src/natools-references__intel.adb
==================================================================
--- src/natools-references__intel.adb
+++ src/natools-references__intel.adb
@@ -113,10 +113,16 @@
    function Is_Empty (Ref : Immutable_Reference) return Boolean is
    begin
       return Ref.Count = null;
    end Is_Empty;
 
+
+   function Is_Last (Ref : Immutable_Reference) return Boolean is
+   begin
+      return Ref.Count.all = 1;
+   end Is_Last;
+
 
    function "=" (Left, Right : Immutable_Reference) return Boolean is
    begin
       return Left.Data = Right.Data;
    end "=";

Index: src/natools-references__intel.ads
==================================================================
--- src/natools-references__intel.ads
+++ src/natools-references__intel.ads
@@ -71,10 +71,15 @@
    procedure Reset (Ref : in out Immutable_Reference);
       --  Empty Ref
 
    function Is_Empty (Ref : Immutable_Reference) return Boolean;
       --  Check whether Ref refers to an actual object
+
+   function Is_Last (Ref : Immutable_Reference) return Boolean;
+      --  Check whether Ref is the last reference to its object.
+      --  WARNING: This is inherently not task-safe if Ref can be
+      --  concurrently accessed.
 
    function "=" (Left, Right : Immutable_Reference) return Boolean;
       --  Check whether Left and Right refer to the same object
 
    function Query (Ref : in Immutable_Reference) return Accessor;

Index: src/natools-references__protected.adb
==================================================================
--- src/natools-references__protected.adb
+++ src/natools-references__protected.adb
@@ -111,10 +111,16 @@
    function Is_Empty (Ref : Immutable_Reference) return Boolean is
    begin
       return Ref.Count = null;
    end Is_Empty;
 
+
+   function Is_Last (Ref : Immutable_Reference) return Boolean is
+   begin
+      return Ref.Count.Get_Value = 1;
+   end Is_Last;
+
 
    function "=" (Left, Right : Immutable_Reference) return Boolean is
    begin
       return Left.Data = Right.Data;
    end "=";

Index: src/natools-references__protected.ads
==================================================================
--- src/natools-references__protected.ads
+++ src/natools-references__protected.ads
@@ -69,10 +69,15 @@
    procedure Reset (Ref : in out Immutable_Reference);
       --  Empty Ref
 
    function Is_Empty (Ref : Immutable_Reference) return Boolean;
       --  Check whether Ref refers to an actual object
+
+   function Is_Last (Ref : Immutable_Reference) return Boolean;
+      --  Check whether Ref is the last reference to its object.
+      --  WARNING: This is inherently not task-safe if Ref can be
+      --  concurrently accessed.
 
    function "=" (Left, Right : Immutable_Reference) return Boolean;
       --  Check whether Left and Right refer to the same object
 
    function Query (Ref : in Immutable_Reference) return Accessor;

Index: src/natools-references__unsafe.adb
==================================================================
--- src/natools-references__unsafe.adb
+++ src/natools-references__unsafe.adb
@@ -109,10 +109,16 @@
    function Is_Empty (Ref : Immutable_Reference) return Boolean is
    begin
       return Ref.Count = null;
    end Is_Empty;
 
+
+   function Is_Last (Ref : Immutable_Reference) return Boolean is
+   begin
+      return Ref.Count.all = 1;
+   end Is_Last;
+
 
    function "=" (Left, Right : Immutable_Reference) return Boolean is
    begin
       return Left.Data = Right.Data;
    end "=";

Index: src/natools-references__unsafe.ads
==================================================================
--- src/natools-references__unsafe.ads
+++ src/natools-references__unsafe.ads
@@ -68,10 +68,13 @@
    procedure Reset (Ref : in out Immutable_Reference);
       --  Empty Ref
 
    function Is_Empty (Ref : Immutable_Reference) return Boolean;
       --  Check whether Ref refers to an actual object
+
+   function Is_Last (Ref : Immutable_Reference) return Boolean;
+      --  Check whether Ref is the last reference to its object
 
    function "=" (Left, Right : Immutable_Reference) return Boolean;
       --  Check whether Left and Right refer to the same object
 
    function Query (Ref : in Immutable_Reference) return Accessor;