Added OPT macro to determine whether C++20's __VA_OPT__ is supported or not. Updated the undocumented variadic IS_EMPTY to use the functionality of __VA_OPT__ if it exists to provide perfect functionality for testing for emptiness.

test/clang_cuda.cu

@@ -9,10 +9,7 @@
 #
 # /* See http://www.boost.org for most recent version. */
 #
-# include <boost/preprocessor/cat.hpp>
-#
-# define BEGIN typedef int BOOST_PP_CAT(test_, __LINE__)[((
-# define END )==1) ? 1 : -1];
+# include <libs/preprocessor/test/test_macro.h>
 
 #if defined(__clang__) && defined(__CUDACC__) && defined(__CUDA__)
 

test/config_info.cpp

@@ -13,6 +13,7 @@
 #include <iomanip>
 #include <string.h>
 #include <boost/preprocessor/stringize.hpp>
+#include <boost/preprocessor/variadic/opt.hpp>
 
 static unsigned int indent = 4;
 static unsigned int width = 40;
@@ -93,6 +94,8 @@ void print_macros()
   PRINT_MACRO(BOOST_PP_CONFIG_FLAGS());
   PRINT_MACRO(BOOST_PP_VARIADICS);
   PRINT_MACRO(BOOST_PP_VARIADICS_MSVC);
+  PRINT_MACRO(BOOST_PP_VARIADICS_MSVC);
+  PRINT_MACRO(BOOST_PP_VARIADIC_OPT());
 }
 
 int main()

test/isempty.cxx

@@ -38,7 +38,20 @@
 
 #if BOOST_PP_VARIADICS
 
-#if BOOST_PP_VARIADICS_MSVC /* Testing the VC++ variadic version */
+# include <boost/preprocessor/variadic/opt.hpp>
+
+#if defined(__cplusplus) && __cplusplus > 201703L && BOOST_PP_VARIADIC_OPT()
+
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN) == 0 END
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN2) == 0 END
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN3) == 0 END
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN4) == 0 END
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN5) == 0 END
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN8) == 0 END
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN9) == 0 END
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN10) == 0 END
+
+#elif BOOST_PP_VARIADICS_MSVC /* Testing the VC++ variadic version */
 
 /* INCORRECT */
 

test/isempty_variadic_standard_failure.cxx

@@ -15,9 +15,19 @@
 #if BOOST_PP_VARIADICS && (BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_STRICT()) && !BOOST_PP_VARIADICS_MSVC
 
 #define FUNC_GEN8(x,y) (1,2,3)
+
+#if defined(__cplusplus) && __cplusplus > 201703L
   
+# include <boost/preprocessor/variadic/opt.hpp>
+
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN8) == BOOST_PP_VARIADIC_OPT() END
+
+#else
+
 BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN8) == 0 END
 
+#endif
+
 #else
   
 BEGIN 1 == 0 END

test/isempty_variadic_standard_failure2.cxx

@@ -16,8 +16,18 @@
 
 #define FUNC_GEN9(x,y,z) anything
   
+#if defined(__cplusplus) && __cplusplus > 201703L
+  
+# include <boost/preprocessor/variadic/opt.hpp>
+
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN9) == BOOST_PP_VARIADIC_OPT() END
+
+#else
+
 BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN9) == 0 END
 
+#endif
+
 #else
   
 BEGIN 1 == 0 END

test/test.h

@@ -14,24 +14,7 @@
 # ifndef BOOST_LIBS_PREPROCESSOR_REGRESSION_TEST_H
 # define BOOST_LIBS_PREPROCESSOR_REGRESSION_TEST_H
 #
-# include <boost/preprocessor/cat.hpp>
+# include <libs/preprocessor/test/test_macro.h>
+# include <libs/preprocessor/test/test_main.h>
 #
-# define BEGIN typedef int BOOST_PP_CAT(test_, __LINE__)[((
-# define END )==1) ? 1 : -1];
-
-#if defined(__cplusplus)
-#include <cstdio>
-#if !defined(_STLP_MSVC) || _STLP_MSVC >= 1300
-namespace std { }
-using namespace std;
-#endif
-#else
-#include <stdio.h>
-#endif
-
-int main(void) {
-    printf("pass " __TIME__);
-    return 0;
-}
-
 # endif

test/test_macro.h

@@ -0,0 +1,22 @@
+# /* Copyright (C) 2001
+#  * Housemarque Oy
+#  * http://www.housemarque.com
+#  *
+#  * Distributed under the Boost Software License, Version 1.0. (See
+#  * accompanying file LICENSE_1_0.txt or copy at
+#  * http://www.boost.org/LICENSE_1_0.txt)
+#  */
+#
+# /* Revised by Paul Mensonides (2002) */
+#
+# /* See http://www.boost.org for most recent version. */
+#
+# ifndef BOOST_LIBS_PREPROCESSOR_REGRESSION_TEST_MACRO_H
+# define BOOST_LIBS_PREPROCESSOR_REGRESSION_TEST_MACRO_H
+#
+# include <boost/preprocessor/cat.hpp>
+#
+# define BEGIN typedef int BOOST_PP_CAT(test_, __LINE__)[((
+# define END )==1) ? 1 : -1];
+#
+# endif

test/test_main.h

@@ -0,0 +1,32 @@
+# /* Copyright (C) 2001
+#  * Housemarque Oy
+#  * http://www.housemarque.com
+#  *
+#  * Distributed under the Boost Software License, Version 1.0. (See
+#  * accompanying file LICENSE_1_0.txt or copy at
+#  * http://www.boost.org/LICENSE_1_0.txt)
+#  */
+#
+# /* Revised by Paul Mensonides (2002) */
+#
+# /* See http://www.boost.org for most recent version. */
+#
+# ifndef BOOST_LIBS_PREPROCESSOR_REGRESSION_TEST_MAIN_H
+# define BOOST_LIBS_PREPROCESSOR_REGRESSION_TEST_MAIN_H
+#
+#if defined(__cplusplus)
+#include <cstdio>
+#if !defined(_STLP_MSVC) || _STLP_MSVC >= 1300
+namespace std { }
+using namespace std;
+#endif
+#else
+#include <stdio.h>
+#endif
+
+int main(void) {
+    printf("pass " __TIME__);
+    return 0;
+}
+
+# endif