[PATCH 2/3] std::latch: reduce internal implementation from ptrdiff_t to int

[Thiago Macieira]

ints can be used as futex on Linux. ptrdiff_t on 64-bit Linux can't.

libstdc++-v3/ChangeLog:

        * include/std/latch: Use int instead of ptrdiff_t
---
 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..f3f73360618 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(4) int _M_a;	// kernel requires 4-byte alignment
   };
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace
-- 
2.30.1