diff --git a/include/fort.h b/include/fort.h
index 928cdf9..dceaabd 100644
--- a/include/fort.h
+++ b/include/fort.h
@@ -56,9 +56,15 @@ SOFTWARE.
 #define FORT_RESTRICT __restrict
 #endif /* if defined(FORT_CLANG_COMPILER) */
 #else
+#if __STDC_VERSION__ < 199901L
 #define FORT_RESTRICT restrict
+#else
+#define FORT_RESTRICT
+#endif /* __STDC_VERSION__ < 199901L */
 #endif /* if defined(__cplusplus) */
 
+
+
 /*
  * Attribute format for argument checking
  */