29 #ifndef _GLIBCXX_LATCH
30 #define _GLIBCXX_LATCH 1
32 #pragma GCC system_header
34 #if __cplusplus > 201703L
39 #if __cpp_lib_atomic_wait
40 namespace std _GLIBCXX_VISIBILITY(default)
42 _GLIBCXX_BEGIN_NAMESPACE_VERSION
44 #define __cpp_lib_latch 201907L
49 static constexpr ptrdiff_t
53 constexpr
explicit latch(ptrdiff_t __expected) noexcept
54 : _M_a(__expected) { }
57 latch(
const latch&) =
delete;
60 _GLIBCXX_ALWAYS_INLINE
void
61 count_down(ptrdiff_t __update = 1)
63 auto const __old = __atomic_impl::fetch_sub(&_M_a,
65 if (__old == __update)
66 __atomic_impl::notify_all(&_M_a);
69 _GLIBCXX_ALWAYS_INLINE
bool
70 try_wait() const noexcept
71 {
return __atomic_impl::load(&_M_a, memory_order::acquire) == 0; }
73 _GLIBCXX_ALWAYS_INLINE
void
76 auto const __pred = [
this] {
return this->try_wait(); };
77 std::__atomic_wait_address(&_M_a, __pred);
80 _GLIBCXX_ALWAYS_INLINE
void
81 arrive_and_wait(ptrdiff_t __update = 1) noexcept
88 alignas(__alignof__(__detail::__platform_wait_t)) __detail::__platform_wait_t _M_a;
90 _GLIBCXX_END_NAMESPACE_VERSION
92 #endif // __cpp_lib_atomic_wait
93 #endif // __cplusplus > 201703L
94 #endif // _GLIBCXX_LATCH
element_type * release()
Bypassing the smart pointer.
constexpr const _Tp & max(const _Tp &, const _Tp &)
This does what you think it does.
__numeric_traits_integer< _Tp > __int_traits
Convenience alias for __numeric_traits<integer-type>.
auto_ptr & operator=(auto_ptr &__a)
auto_ptr assignment operator.