These variable templates give warnings in C++11 mode when
-Wsystem-headers is used:
In file included from /home/jwakely/gcc/7/include/c++/7.0.0/memory:77:0,
from vt.cc:1:
/home/jwakely/gcc/7/include/c++/7.0.0/bits/uses_allocator.h:130:20: warning:
variable templates only available with -std=c++14 or -std=gnu++14
constexpr bool __is_uses_allocator_constructible_v =
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/jwakely/gcc/7/include/c++/7.0.0/bits/uses_allocator.h:141:20: warning:
variable templates only available with -std=c++14 or -std=gnu++14
constexpr bool __is_nothrow_uses_allocator_constructible_v =
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We don't need them, so let's only define them for C++14 and up.
* include/bits/uses_allocator.h (__is_uses_allocator_constructible_v)
(__is_nothrow_uses_allocator_constructible_v): Only define for C++14
and later.
Tested powerpc64le-linux, committed to trunk.
commit b19fd14727318d5d6f3a411a2a600f89d07ab28a
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Tue Oct 18 12:31:11 2016 +0100
Don't define uses-allocator variable templates in C++11
* include/bits/uses_allocator.h (__is_uses_allocator_constructible_v)
(__is_nothrow_uses_allocator_constructible_v): Only define for C++14
and later.
diff --git a/libstdc++-v3/include/bits/uses_allocator.h
b/libstdc++-v3/include/bits/uses_allocator.h
index c7d14f3..612c53c 100644
--- a/libstdc++-v3/include/bits/uses_allocator.h
+++ b/libstdc++-v3/include/bits/uses_allocator.h
@@ -126,9 +126,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
: __is_uses_allocator_predicate<is_constructible, _Tp, _Alloc, _Args...>
{ };
+#if __cplusplus >= 201402L
template<typename _Tp, typename _Alloc, typename... _Args>
constexpr bool __is_uses_allocator_constructible_v =
__is_uses_allocator_constructible<_Tp, _Alloc, _Args...>::value;
+#endif // C++14
template<typename _Tp, typename _Alloc, typename... _Args>
struct __is_nothrow_uses_allocator_constructible
@@ -137,9 +139,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ };
+#if __cplusplus >= 201402L
template<typename _Tp, typename _Alloc, typename... _Args>
constexpr bool __is_nothrow_uses_allocator_constructible_v =
__is_nothrow_uses_allocator_constructible<_Tp, _Alloc, _Args...>::value;
+#endif // C++14
template<typename _Tp, typename... _Args>
void __uses_allocator_construct_impl(__uses_alloc0 __a, _Tp* __ptr,
