+#ifndef BOOST_SP_NO_SYNC
+
+#if defined( __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 )
+
+# define BOOST_SP_HAS_SYNC
+
+#elif defined( __IBMCPP__ ) && ( __IBMCPP__ >= 1210 )
+
+# define BOOST_SP_HAS_SYNC
+
+#elif defined( __GNUC__ ) && ( __GNUC__ * 100 + __GNUC_MINOR__ >= 401 )