diff --git a/src/memfile.c b/src/memfile.c
index abb7c3f..4707969 100644
--- a/src/memfile.c
+++ b/src/memfile.c
@@ -594,13 +594,10 @@
 	}
 	else
 # endif
-	    // OpenNT is strictly POSIX (Benzinger)
-	    // Tandem/Himalaya NSK-OSS doesn't have sync()
-	    // No sync() on Stratus VOS
-# if defined(__OPENNT) || defined(__TANDEM) || defined(__VOS__)
-	    fflush(NULL);
-# else
+# ifdef HAVE_SYNC
 	    sync();
+# else
+	    fflush(NULL);
 # endif
 #endif
 #ifdef VMS