diff --git a/ACE/ace/Event_Handler.h b/ACE/ace/Event_Handler.h
index 3dc5f1f8e1b94..6d70762a04a4f 100644
--- a/ACE/ace/Event_Handler.h
+++ b/ACE/ace/Event_Handler.h
@@ -19,9 +19,8 @@
 #endif /* ACE_LACKS_PRAGMA_ONCE */
 
 #include "ace/os_include/os_signal.h"
-#include "ace/Atomic_Op.h"
 #include "ace/OS_NS_Thread.h"
-#include "ace/Synch_Traits.h"
+#include <atomic>
 
 ACE_BEGIN_VERSIONED_NAMESPACE_DECL
 
@@ -286,7 +285,7 @@ class ACE_Export ACE_Event_Handler
                      int priority = ACE_Event_Handler::LO_PRIORITY);
 
   /// Typedef for implementation of reference counting.
-  typedef ACE_Atomic_Op<ACE_SYNCH_MUTEX, Reference_Count> Atomic_Reference_Count;
+  typedef std::atomic<Reference_Count> Atomic_Reference_Count;
 
   /// Reference count.
   Atomic_Reference_Count reference_count_;
diff --git a/ACE/ace/Reactor.h b/ACE/ace/Reactor.h
index 77eb07ab93d2e..2a1242c655eb5 100644
--- a/ACE/ace/Reactor.h
+++ b/ACE/ace/Reactor.h
@@ -30,6 +30,7 @@
 
 // Get ACE_Time_Value in
 #include "ace/Time_Value.h"
+#include "ace/Synch_Traits.h"
 
 ACE_BEGIN_VERSIONED_NAMESPACE_DECL
 
diff --git a/ACE/ace/Reactor_Impl.h b/ACE/ace/Reactor_Impl.h
index b6513e5ec4b9e..dcb18c666b46f 100644
--- a/ACE/ace/Reactor_Impl.h
+++ b/ACE/ace/Reactor_Impl.h
@@ -24,6 +24,7 @@
 // Event_Handler.h contains the definition of ACE_Reactor_Mask
 #include "ace/Event_Handler.h"
 #include "ace/Countdown_Time.h"
+#include "ace/Synch_Traits.h"
 
 ACE_BEGIN_VERSIONED_NAMESPACE_DECL
 
diff --git a/ACE/tests/MT_Reference_Counted_Event_Handler_Test.cpp b/ACE/tests/MT_Reference_Counted_Event_Handler_Test.cpp
index bae36ea9c0ee0..8a25fcf5b10f3 100644
--- a/ACE/tests/MT_Reference_Counted_Event_Handler_Test.cpp
+++ b/ACE/tests/MT_Reference_Counted_Event_Handler_Test.cpp
@@ -296,7 +296,7 @@ Sender::Sender (ACE_HANDLE handle,
   if (debug)
     ACE_DEBUG ((LM_DEBUG,
                 ACE_TEXT ("(%t) Reference count in Sender::Sender() is %d\n"),
-                this->reference_count_.value ()));
+                this->reference_count_.load ()));
 }
 
 Sender::~Sender (void)
@@ -304,7 +304,7 @@ Sender::~Sender (void)
   if (debug)
     ACE_DEBUG ((LM_DEBUG,
                 ACE_TEXT ("(%t) Reference count in ~Sender::Sender() is %d\n"),
-                this->reference_count_.value ()));
+                this->reference_count_.load ()));
 
   // Close the socket that we are responsible for.
   ACE_OS::closesocket (this->handle_);
@@ -316,7 +316,7 @@ Sender::handle_input (ACE_HANDLE)
   if (debug)
     ACE_DEBUG ((LM_DEBUG,
                 ACE_TEXT ("(%t) Reference count in Sender::handle_input() is %d\n"),
-                this->reference_count_.value ()));
+                this->reference_count_.load ()));
 
   //
   // In this test, this method is only called when the connection has
@@ -417,7 +417,7 @@ Receiver::Receiver (ACE_Thread_Manager &thread_manager,
   if (debug)
     ACE_DEBUG ((LM_DEBUG,
                 ACE_TEXT ("(%t) Reference count in Receiver::Receiver() is %d\n"),
-                this->reference_count_.value ()));
+                this->reference_count_.load ()));
 }
 
 Receiver::~Receiver (void)
@@ -425,7 +425,7 @@ Receiver::~Receiver (void)
   if (debug)
     ACE_DEBUG ((LM_DEBUG,
                 ACE_TEXT ("(%t) Reference count in ~Receiver::Receiver() is %d\n"),
-                this->reference_count_.value ()));
+                this->reference_count_.load ()));
 
   // Close the socket that we are responsible for.
   ACE_OS::closesocket (this->handle_);
diff --git a/ACE/tests/MT_Reference_Counted_Notify_Test.cpp b/ACE/tests/MT_Reference_Counted_Notify_Test.cpp
index 6d6b67a903002..609e78681ae80 100644
--- a/ACE/tests/MT_Reference_Counted_Notify_Test.cpp
+++ b/ACE/tests/MT_Reference_Counted_Notify_Test.cpp
@@ -60,7 +60,7 @@ Reference_Counted_Event_Handler::Reference_Counted_Event_Handler (void)
       ((LM_DEBUG,
         ACE_TEXT ("Reference count in Reference_Counted_Event_Handler() ")
         ACE_TEXT ("is %d\n"),
-        this->reference_count_.value ()));
+        this->reference_count_.load ()));
 }
 
 Reference_Counted_Event_Handler::~Reference_Counted_Event_Handler (void)
@@ -70,14 +70,14 @@ Reference_Counted_Event_Handler::~Reference_Counted_Event_Handler (void)
       ((LM_DEBUG,
         ACE_TEXT ("Reference count in ~Reference_Counted_Event_Handler() ")
         ACE_TEXT ("is %d\n"),
-        this->reference_count_.value ()));
+        this->reference_count_.load ()));
 
-  if (0 != this->reference_count_.value ())
+  if (0 != this->reference_count_.load ())
     ACE_ERROR
       ((LM_ERROR,
         ACE_TEXT ("Reference count in ~Reference_Counted_Event_Handler() ")
         ACE_TEXT ("should be 0 but is %d\n"),
-        this->reference_count_.value ()));
+        this->reference_count_.load ()));
 }
 
 int
@@ -88,14 +88,14 @@ Reference_Counted_Event_Handler::handle_input (ACE_HANDLE)
       ((LM_DEBUG,
         ACE_TEXT ("Reference count in Reference_Counted_Event_Handler::")
         ACE_TEXT ("handle_input() is %d\n"),
-        this->reference_count_.value ()));
+        this->reference_count_.load ()));
 
-  if (2 != this->reference_count_.value ())
+  if (2 != this->reference_count_.load ())
     ACE_ERROR
       ((LM_ERROR,
         ACE_TEXT ("Reference count in Reference_Counted_Event_Handler::")
         ACE_TEXT ("handle_input() should be 2 but is %d\n"),
-        this->reference_count_.value ()));
+        this->reference_count_.load ()));
 
   return 0;
 }
@@ -109,7 +109,7 @@ Reference_Counted_Event_Handler::add_reference (void)
   if (debug)
     ACE_DEBUG ((LM_DEBUG,
                 ACE_TEXT ("Reference count after add_reference() is %d\n"),
-                this->reference_count_.value ()));
+                this->reference_count_.load ()));
 
   return reference_count;
 }
diff --git a/ACE/tests/Reference_Counted_Event_Handler_Test.cpp b/ACE/tests/Reference_Counted_Event_Handler_Test.cpp
index 356fcacc7ae02..4e5dc94ae297b 100644
--- a/ACE/tests/Reference_Counted_Event_Handler_Test.cpp
+++ b/ACE/tests/Reference_Counted_Event_Handler_Test.cpp
@@ -78,14 +78,14 @@ Reference_Counted_Event_Handler::Reference_Counted_Event_Handler (int &events)
 
   ACE_DEBUG ((LM_DEBUG,
               "Reference count in Reference_Counted_Event_Handler() is %d\n",
-              this->reference_count_.value ()));
+              this->reference_count_.load ()));
 }
 
 Reference_Counted_Event_Handler::~Reference_Counted_Event_Handler (void)
 {
   ACE_DEBUG ((LM_DEBUG,
               "Reference count in ~Reference_Counted_Event_Handler() is %d\n",
-              this->reference_count_.value ()));
+              this->reference_count_.load ()));
 
   this->pipe_.close ();
 }
@@ -95,7 +95,7 @@ Reference_Counted_Event_Handler::handle_input (ACE_HANDLE)
 {
   ACE_DEBUG ((LM_DEBUG,
               "Reference count in Reference_Counted_Event_Handler::handle_input() is %d\n",
-              this->reference_count_.value ()));
+              this->reference_count_.load ()));
 
   --this->events_;
 
@@ -126,7 +126,7 @@ Reference_Counted_Event_Handler::handle_output (ACE_HANDLE)
 {
   ACE_DEBUG ((LM_DEBUG,
               "Reference count in Reference_Counted_Event_Handler::handle_output() is %d\n",
-              this->reference_count_.value ()));
+              this->reference_count_.load ()));
 
   --this->events_;
 
@@ -152,7 +152,7 @@ Reference_Counted_Event_Handler::handle_timeout (const ACE_Time_Value &,
   ACE_DEBUG ((LM_DEBUG,
               "Reference count in Reference_Counted_Event_Handler::handle_timeout() for arg = %C is %d\n",
               (const char *) arg,
-              this->reference_count_.value ()));
+              this->reference_count_.load ()));
 
   --this->events_;
 
@@ -176,7 +176,7 @@ Reference_Counted_Event_Handler::handle_close (ACE_HANDLE handle,
               "Reference count is %d\n",
               handle,
               masks,
-              this->reference_count_.value ()));
+              this->reference_count_.load ()));
 
   return 0;
 }
@@ -189,7 +189,7 @@ Reference_Counted_Event_Handler::add_reference (void)
 
   ACE_DEBUG ((LM_DEBUG,
               "Reference count after add_reference() is %d\n",
-              this->reference_count_.value ()));
+              this->reference_count_.load ()));
 
   return reference_count;
 }
@@ -854,7 +854,7 @@ Closed_In_Upcall_Event_Handler::handle_close (ACE_HANDLE handle,
               ACE_TEXT ("Reference count is %d\n"),
               handle,
               masks,
-              this->reference_count_.value ()));
+              this->reference_count_.load ()));
 
   return 0;
 }
@@ -867,7 +867,7 @@ Closed_In_Upcall_Event_Handler::add_reference (void)
 
   ACE_DEBUG ((LM_DEBUG,
               ACE_TEXT ("Reference count after add_reference() is %d\n"),
-              this->reference_count_.value ()));
+              this->reference_count_.load ()));
 
   return reference_count;
 }
diff --git a/ACE/tests/Timer_Queue_Reference_Counting_Test.cpp b/ACE/tests/Timer_Queue_Reference_Counting_Test.cpp
index 223681ccd20a4..c1e0925d2038e 100644
--- a/ACE/tests/Timer_Queue_Reference_Counting_Test.cpp
+++ b/ACE/tests/Timer_Queue_Reference_Counting_Test.cpp
@@ -70,7 +70,7 @@ Reference_Counted_Event_Handler::Reference_Counted_Event_Handler (int expected_n
   if (debug)
     ACE_DEBUG ((LM_DEBUG,
                 "Reference count in Reference_Counted_Event_Handler() is %d\n",
-                this->reference_count_.value ()));
+                this->reference_count_.load ()));
 }
 
 Reference_Counted_Event_Handler::~Reference_Counted_Event_Handler (void)
@@ -78,7 +78,7 @@ Reference_Counted_Event_Handler::~Reference_Counted_Event_Handler (void)
   if (debug)
     ACE_DEBUG ((LM_DEBUG,
                 "Reference count in ~Reference_Counted_Event_Handler() is %d\n",
-                this->reference_count_.value ()));
+                this->reference_count_.load ()));
 
   if (this->expected_number_of_handle_close_calls_ != -1)
     ACE_TEST_ASSERT (this->number_of_handle_close_calls_ ==
@@ -93,7 +93,7 @@ Reference_Counted_Event_Handler::handle_timeout (const ACE_Time_Value &,
     ACE_DEBUG ((LM_DEBUG,
                 "Reference count in Reference_Counted_Event_Handler::handle_timeout() for arg = %C is %d\n",
                 (const char *) arg,
-                this->reference_count_.value ()));
+                this->reference_count_.load ()));
 
   return 0;
 }
@@ -108,7 +108,7 @@ Reference_Counted_Event_Handler::handle_close (ACE_HANDLE handle,
                 "Reference count is %d\n",
                 handle,
                 masks,
-                this->reference_count_.value ()));
+                this->reference_count_.load ()));
 
   ++this->number_of_handle_close_calls_;
 
diff --git a/ACE/tests/WFMO_Reactor_Test.cpp b/ACE/tests/WFMO_Reactor_Test.cpp
index ee85fa70acb7a..e76d831ee6d75 100644
--- a/ACE/tests/WFMO_Reactor_Test.cpp
+++ b/ACE/tests/WFMO_Reactor_Test.cpp
@@ -37,7 +37,7 @@ Event_Handler::Event_Handler (ACE_Reactor &reactor)
 
   ACE_DEBUG ((LM_DEBUG,
               "Reference count in Event_Handler() is %d\n",
-              this->reference_count_.value ()));
+              this->reference_count_.load ()));
 
   this->reactor (&reactor);
 
@@ -62,7 +62,7 @@ Event_Handler::~Event_Handler (void)
 {
   ACE_DEBUG ((LM_DEBUG,
               "Reference count in ~Event_Handler() is %d\n",
-              this->reference_count_.value ()));
+              this->reference_count_.load ()));
 
   ++number_of_closes;
 }
diff --git a/TAO/tao/GUIResource_Factory.cpp b/TAO/tao/GUIResource_Factory.cpp
index 27f7a00886152..903f59995df91 100644
--- a/TAO/tao/GUIResource_Factory.cpp
+++ b/TAO/tao/GUIResource_Factory.cpp
@@ -1,5 +1,6 @@
 #include "tao/GUIResource_Factory.h"
 #include "ace/Reactor.h"
+#include "ace/Guard_T.h"
 #include "tao/debug.h"
 
 TAO_BEGIN_VERSIONED_NAMESPACE_DECL