标准库标头 <semaphore> (C++20)

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C++
 
标准库头
通用工具
<any> (C++17)
<bitset>
<bit> (C++20)
<charconv> (C++17)
<expected> (C++23)
<format> (C++20)
<functional>
<optional> (C++17)
<stdbit.h> (C++26)
<tuple> (C++11)
<typeindex> (C++11)
<utility>
<variant> (C++17)
容器
<array> (C++11)
<deque>
<flat_map> (C++23)
<flat_set> (C++23)
<forward_list> (C++11)
<hive> (C++26)
<inplace_vector> (C++26)   
<list>
<map>
<mdspan> (C++23)
<queue>
<set>
<span> (C++20)
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<unordered_map> (C++11)
<unordered_set> (C++11)
<vector>
迭代器
<iterator>
范围
<generator> (C++23)
<ranges> (C++20)
 

此头文件是线程支持库的一部分。

类

(C++20)
 实现非负资源计数的信号量
(类模板) [编辑]
(C++20)
 仅拥有两个状态的信号量
(typedef) [编辑]

概要

namespace std {
  template<ptrdiff_t LeastMaxValue = /* 实现定义 */>
    class counting_semaphore;

  using binary_semaphore = counting_semaphore<1>;
}

类模板 std::counting_semaphore

namespace std {
  template<ptrdiff_t LeastMaxValue = /* 实现定义 */>
  class counting_semaphore {
  public:
    static constexpr ptrdiff_t max() noexcept;

    constexpr explicit counting_semaphore(ptrdiff_t desired);
    ~counting_semaphore();

    counting_semaphore(const counting_semaphore&) = delete;
    counting_semaphore& operator=(const counting_semaphore&) = delete;

    void release(ptrdiff_t update = 1);
    void acquire();
    bool try_acquire() noexcept;
    template<class Rep, class Period>
      bool try_acquire_for(const chrono::duration<Rep, Period>& rel_time);
    template<class Clock, class Duration>
      bool try_acquire_until(const chrono::time_point<Clock, Duration>& abs_time);

  private:
    ptrdiff_t counter;          // 仅用于阐释
  };
}