[PATCH 1/5] std::latch: reduce internal implementation from ptrdiff_t to int

[Jonathan Wakely]

On 26/02/21 07:59 -0800, Thiago Macieira via Libstdc++ wrote:
>ints can be used as futex on Linux. ptrdiff_t on 64-bit Linux can't.

Yes, we should do this for GCC 11.


> libstdc++-v3/include/std/latch | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
>diff --git a/libstdc++-v3/include/std/latch b/libstdc++-v3/include/std/latch
>index ef8c301e5e9..156aea5c5e5 100644
>--- a/libstdc++-v3/include/std/latch
>+++ b/libstdc++-v3/include/std/latch
>@@ -48,7 +48,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>   public:
>     static constexpr ptrdiff_t
>     max() noexcept
>-    { return __gnu_cxx::__int_traits<ptrdiff_t>::__max; }
>+    { return __gnu_cxx::__int_traits<int>::__max; }
>
>     constexpr explicit latch(ptrdiff_t __expected) noexcept
>       : _M_a(__expected) { }
>@@ -85,7 +85,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>     }
>
>   private:
>-    alignas(__alignof__(ptrdiff_t)) ptrdiff_t _M_a;
>+    alignas(__alignof__(int)) int _M_a;
>   };
> _GLIBCXX_END_NAMESPACE_VERSION
> } // namespace
>-- 
>2.30.1
>