diff --git a/lib/cmock_generator_plugin_return_thru_ptr.rb b/lib/cmock_generator_plugin_return_thru_ptr.rb
index 4ecc983..9363e4c 100644
--- a/lib/cmock_generator_plugin_return_thru_ptr.rb
+++ b/lib/cmock_generator_plugin_return_thru_ptr.rb
@@ -79,7 +79,7 @@ class CMockGeneratorPluginReturnThruPtr
       arg_name = arg[:name]
       next unless @utils.ptr_or_str?(arg[:type]) && !(arg[:const?])
 
-      dest_cast = arg[:volatile?] ? '(void*)(uintptr_t)' : '(void*)'
+      dest_cast = arg[:volatile?] ? '(void*)(CMOCK_MEM_PTR_AS_INT)' : '(void*)'
       lines << "  if (Mock.#{function[:name]}_IgnoreBool && cmock_call_instance != NULL &&\n"
       lines << "      cmock_call_instance->ReturnThruPtr_#{arg_name}_Used)\n"
       lines << "  {\n"
@@ -134,7 +134,7 @@ class CMockGeneratorPluginReturnThruPtr
       arg_name = arg[:name]
       next unless @utils.ptr_or_str?(arg[:type]) && !(arg[:const?])
 
-      dest_cast = arg[:volatile?] ? '(void*)(uintptr_t)' : '(void*)'
+      dest_cast = arg[:volatile?] ? '(void*)(CMOCK_MEM_PTR_AS_INT)' : '(void*)'
       lines << "  if (cmock_call_instance->ReturnThruPtr_#{arg_name}_Used)\n"
       lines << "  {\n"
       lines << "    UNITY_TEST_ASSERT_NOT_NULL(#{arg_name}, cmock_line, CMockStringPtrIsNULL);\n"
diff --git a/test/unit/cmock_generator_plugin_return_thru_ptr_test.rb b/test/unit/cmock_generator_plugin_return_thru_ptr_test.rb
index c6a7a06..f1dfbb0 100644
--- a/test/unit/cmock_generator_plugin_return_thru_ptr_test.rb
+++ b/test/unit/cmock_generator_plugin_return_thru_ptr_test.rb
@@ -252,14 +252,14 @@ describe CMockGeneratorPluginReturnThruPtr, "Verify CMockGeneratorPluginReturnTh
     assert_equal(expected, returned)
   end
 
-  it "uses (void*)(uintptr_t) cast in mock_implementation for volatile pointer arg" do
+  it "uses (void*)(CMOCK_MEM_PTR_AS_INT) cast in mock_implementation for volatile pointer arg" do
     volatile_ptr_func_expect()
 
     expected =
       "  if (cmock_call_instance->ReturnThruPtr_foo_handle_Used)\n" +
       "  {\n" +
       "    UNITY_TEST_ASSERT_NOT_NULL(foo_handle, cmock_line, CMockStringPtrIsNULL);\n" +
-      "    CMOCK_MEMCPY((void*)(uintptr_t)foo_handle, (const void*)cmock_call_instance->ReturnThruPtr_foo_handle_Val,\n" +
+      "    CMOCK_MEMCPY((void*)(CMOCK_MEM_PTR_AS_INT)foo_handle, (const void*)cmock_call_instance->ReturnThruPtr_foo_handle_Val,\n" +
       "      cmock_call_instance->ReturnThruPtr_foo_handle_Size);\n" +
       "  }\n"