Define __cpp_lib_byte feature-test macro

	* include/c_global/cstddef: Define __cpp_lib_byte feature-test macro.
	* testsuite/18_support/byte/requirements.cc: Check macro.

From-SVN: r253952

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index ba43a4b..179361d 100644 (file)
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,8 @@
+2017-10-20  Jonathan Wakely  <jwakely@redhat.com>
+
+       * include/c_global/cstddef: Define __cpp_lib_byte feature-test macro.
+       * testsuite/18_support/byte/requirements.cc: Check macro.
+
 2017-10-19  Jonathan Wakely  <jwakely@redhat.com>
 
        * testsuite/experimental/filesystem/iterators/

diff --git a/libstdc++-v3/include/c_global/cstddef b/libstdc++-v3/include/c_global/cstddef
index 09754ee..11d268b 100644 (file)
--- a/libstdc++-v3/include/c_global/cstddef
+++ b/libstdc++-v3/include/c_global/cstddef
@@ -57,9 +57,11 @@ namespace std
 }
 #endif
 
-#if __cplusplus > 201402L
+#if __cplusplus >= 201703L
 namespace std
 {
+#define __cpp_lib_byte 201603
+
   /// std::byte
   enum class byte : unsigned char {};
 

diff --git a/libstdc++-v3/testsuite/18_support/byte/requirements.cc b/libstdc++-v3/testsuite/18_support/byte/requirements.cc
index 4cb05df..74c8b64 100644 (file)
--- a/libstdc++-v3/testsuite/18_support/byte/requirements.cc
+++ b/libstdc++-v3/testsuite/18_support/byte/requirements.cc
@@ -20,6 +20,12 @@
 
 #include <cstddef>
 
+#ifndef __cpp_lib_byte
+# error "Feature-test macro for byte missing"
+#elif __cpp_lib_byte != 201603
+# error "Feature-test macro for byte has wrong value"
+#endif
+
 static_assert( sizeof(std::byte) == sizeof(unsigned char) );
 static_assert( alignof(std::byte) == alignof(unsigned char) );