From 4cce94a84ec47903570754e2324fa46415d23d2a Mon Sep 17 00:00:00 2001
From: Edward Diener <eldlistmailingz@tropicsoft.com>
Date: Fri, 27 Sep 2019 09:44:15 -0400
Subject: [PATCH] Segregate C20 macros code from other macros for
 BOOST_PP_IS_EMPTY

---
 .../facilities/is_empty_variadic.hpp          | 26 +++++++++++--------
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/include/boost/preprocessor/facilities/is_empty_variadic.hpp b/include/boost/preprocessor/facilities/is_empty_variadic.hpp
index f194a3f..4beb3c9 100644
--- a/include/boost/preprocessor/facilities/is_empty_variadic.hpp
+++ b/include/boost/preprocessor/facilities/is_empty_variadic.hpp
@@ -37,6 +37,7 @@
 /**/
 #define BOOST_PP_IS_EMPTY_ZERO(param) 0
 # else
+# if defined(__cplusplus) && __cplusplus > 201703L
 # include <boost/preprocessor/variadic/opt.hpp>
 #define BOOST_PP_IS_EMPTY(...) \
     BOOST_PP_DETAIL_IS_EMPTY_IIF \
@@ -49,6 +50,20 @@
       ) \
     (__VA_ARGS__) \
 /**/
+#define BOOST_PP_IS_EMPTY_FUNCTION2(...) \
+    __VA_OPT__(0,) 1 \
+/**/
+#define BOOST_PP_IS_EMPTY_FUNCTION(...) \
+    BOOST_PP_IS_EMPTY_FUNCTION2(__VA_ARGS__) \
+/**/
+#define BOOST_PP_IS_EMPTY_OPT(...) \
+    BOOST_PP_VARIADIC_OPT_ELEM0(BOOST_PP_IS_EMPTY_FUNCTION(__VA_ARGS__),) \
+/**/
+# else
+#define BOOST_PP_IS_EMPTY(...) \
+    BOOST_PP_IS_EMPTY_NO_OPT(__VA_ARGS__) \
+/**/
+# endif /* defined(__cplusplus) && __cplusplus > 201703L */
 #define BOOST_PP_IS_EMPTY_NO_OPT(...) \
     BOOST_PP_DETAIL_IS_EMPTY_IIF \
       ( \
@@ -64,17 +79,6 @@
     (__VA_ARGS__) \
 /**/
 #define BOOST_PP_IS_EMPTY_ZERO(...) 0
-# if defined(__cplusplus) && __cplusplus > 201703L
-#define BOOST_PP_IS_EMPTY_FUNCTION2(...) \
-    __VA_OPT__(0,) 1 \
-/**/
-#endif
-#define BOOST_PP_IS_EMPTY_FUNCTION(...) \
-    BOOST_PP_IS_EMPTY_FUNCTION2(__VA_ARGS__) \
-/**/
-#define BOOST_PP_IS_EMPTY_OPT(...) \
-    BOOST_PP_VARIADIC_OPT_ELEM0(BOOST_PP_IS_EMPTY_FUNCTION(__VA_ARGS__),) \
-/**/
 # endif /* BOOST_PP_VARIADICS_MSVC && _MSC_VER <= 1400 */
 # endif /* BOOST_PP_VARIADICS */
 # endif /* BOOST_PREPROCESSOR_FACILITIES_IS_EMPTY_VARIADIC_HPP */