std::once_flag - cppreference.com

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hardware_destructive_interference_sizehardware_constructive_interference_size

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原子类型
atomic (C++11)
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atomic_flag (C++11)
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atomic_storeatomic_store_explicit (C++11)(C++11)
atomic_loadatomic_load_explicit (C++11)(C++11)
atomic_exchangeatomic_exchange_explicit (C++11)(C++11)
atomic_compare_exchange_weakatomic_compare_exchange_weak_explicitatomic_compare_exchange_strongatomic_compare_exchange_strong_explicit (C++11)(C++11)(C++11)(C++11)
atomic_fetch_addatomic_fetch_add_explicit (C++11)(C++11)
atomic_fetch_subatomic_fetch_sub_explicit (C++11)(C++11)
atomic_fetch_andatomic_fetch_and_explicit (C++11)(C++11)
atomic_fetch_oratomic_fetch_or_explicit (C++11)(C++11)
atomic_fetch_xoratomic_fetch_xor_explicit (C++11)(C++11)
atomic_fetch_maxatomic_fetch_max_explicit (C++26)(C++26)
atomic_fetch_minatomic_fetch_min_explicit (C++26)(C++26)
atomic_is_lock_free (C++11)
atomic_waitatomic_wait_explicit (C++20)(C++20)
atomic_notify_one (C++20)
atomic_notify_all (C++20)
原子标志的自由函数
atomic_flag_test_and_setatomic_flag_test_and_set_explicit (C++11)(C++11)
atomic_flag_clearatomic_flag_clear_explicit (C++11)(C++11)
atomic_flag_testatomic_flag_test_explicit (C++20)(C++20)
atomic_flag_waitatomic_flag_wait_explicit (C++20)(C++20)
atomic_flag_notify_one (C++20)
atomic_flag_notify_all (C++20)

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在标头 `<mutex>` 定义
class once_flag;		(C++11 起)

类 std::once_flag 是 std::call_once 的辅助结构体。

传递给多次 std::call_once 调用的 std::once_flag 类型的对象，允许这些调用彼此协调，从而令只有一次调用实际完成运行。

std::once_flag 既不可复制亦不可移动。

成员函数

std::once_flag::once_flag

constexpr once_flag() noexcept;

构造 once_flag 对象。设置内部状态为指示尚未调用函数。

参数

（无）

参阅

call_once (C++11)	仅调用函数一次，即使从多个线程调用 (函数模板) [编辑]
once_flag 的 C 文档