30#define _GLIBCXX_LATCH 1
32#pragma GCC system_header
36#if __cplusplus > 201703L
41#if __cpp_lib_atomic_wait
42namespace std _GLIBCXX_VISIBILITY(default)
44_GLIBCXX_BEGIN_NAMESPACE_VERSION
46#define __cpp_lib_latch 201907L
51 static constexpr ptrdiff_t
55 constexpr explicit latch(ptrdiff_t __expected) noexcept
56 : _M_a(__expected) { }
59 latch(
const latch&) =
delete;
60 latch& operator=(
const latch&) =
delete;
62 _GLIBCXX_ALWAYS_INLINE
void
63 count_down(ptrdiff_t __update = 1)
65 auto const __old = __atomic_impl::fetch_sub(&_M_a,
66 __update, memory_order::release);
67 if (__old == __update)
68 __atomic_impl::notify_all(&_M_a);
71 _GLIBCXX_ALWAYS_INLINE
bool
72 try_wait() const noexcept
73 {
return __atomic_impl::load(&_M_a, memory_order::acquire) == 0; }
75 _GLIBCXX_ALWAYS_INLINE
void
78 auto const __pred = [
this] {
return this->try_wait(); };
79 std::__atomic_wait_address(&_M_a, __pred);
82 _GLIBCXX_ALWAYS_INLINE
void
83 arrive_and_wait(ptrdiff_t __update = 1) noexcept
90 alignas(__alignof__(__detail::__platform_wait_t)) __detail::__platform_wait_t _M_a;
92_GLIBCXX_END_NAMESPACE_VERSION
constexpr const _Tp & max(const _Tp &, const _Tp &)
This does what you think it does.
ISO C++ entities toplevel namespace is std.
__numeric_traits_integer< _Tp > __int_traits
Convenience alias for __numeric_traits<integer-type>.