On 14/06/18 15:00 +0100, Jonathan Wakely wrote:
During the review of P0941R2 in Rapperswil we noticed that SD-6 puts
the macro __cpp_lib_tuple_element_t in <utility>, but it should be in
<tuple>.
* include/std/tuple (__cpp_lib_tuple_element_t): Move feature test
macro from <utility> and change type to long.
* include/std/utility (__cpp_lib_tuple_element_t): Remove.
* testsuite/20_util/tuple/tuple_element_t.cc: Check for feature test
macro.
Tested x86_64-linux, committed to trunk.
This caused some tests to fail (but not for me, maybe because of
precompiled headers). I'm moving the macro and the alias template back
to <utility>, but keeping the change of the macro value from int to
long (as required by the C++2a working paper).
Tested powerpc64le-linux, committed to trunk.
commit 378a13153d1761f68c5c783d7502761b37e711f5
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Thu Jun 14 19:44:42 2018 +0100
Partially revert move of std::tuple_element_t to <tuple>
Defining std::tuple_element_t in <utility> makes it available wherever
std::tuple_element is available.
* include/std/tuple (__cpp_lib_tuple_element_t, tuple_element_t):
Move back to <utility>.
* include/std/utility (__cpp_lib_tuple_element_t. tuple_element_t):
Restore to here.
diff --git a/libstdc++-v3/include/std/tuple b/libstdc++-v3/include/std/tuple
index 0f890504889..dd7daf7f1cf 100644
--- a/libstdc++-v3/include/std/tuple
+++ b/libstdc++-v3/include/std/tuple
@@ -1298,13 +1298,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
"tuple index is in range");
};
-#if __cplusplus >= 201402L
-#define __cpp_lib_tuple_element_t 201402L
-
- template<size_t __i, typename _Tp>
- using tuple_element_t = typename tuple_element<__i, _Tp>::type;
-#endif
-
template<std::size_t __i, typename _Head, typename... _Tail>
constexpr _Head&
__get_helper(_Tuple_impl<__i, _Head, _Tail...>& __t) noexcept
diff --git a/libstdc++-v3/include/std/utility b/libstdc++-v3/include/std/utility
index 7bf80de3745..17e7d4cbe7a 100644
--- a/libstdc++-v3/include/std/utility
+++ b/libstdc++-v3/include/std/utility
@@ -135,6 +135,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
typedef typename add_cv<__tuple_element_t<__i, _Tp>>::type type;
};
+#if __cplusplus >= 201402L
+// The standard says this macro and alias template should be in <tuple>
+// but we define them here, to be available when the partial specializations
+// of tuple_element<pair<T,U>> and tuple_element<array<T,N>> are defined.
+#define __cpp_lib_tuple_element_t 201402L
+
+ template<std::size_t __i, typename _Tp>
+ using tuple_element_t = typename tuple_element<__i, _Tp>::type;
+#endif
+
// Various functions which give std::pair a tuple-like interface.
/// Partial specialization for std::pair
