std::counting_semaphore<LeastMaxValue>::try_acquire

 

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原子型別 atomic (C++11) atomic_ref (C++20) atomic_flag (C++11) 原子型別的初始化 atomic_init (C++11)(C++20 中已棄用) ATOMIC_VAR_INIT (C++11)(C++20 中已棄用) ATOMIC_FLAG_INIT (C++11) 記憶體排序 memory_order (C++11) kill_dependency (C++11)(C++26 中已棄用) atomic_thread_fence (C++11) atomic_signal_fence (C++11) 原子操作的自由函式 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) 原子標誌的自由函式 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)

 

std::counting_semaphore

成員函式

counting_semaphore::counting_semaphore

counting_semaphore::~counting_semaphore

操作

counting_semaphore::release

counting_semaphore::acquire

counting_semaphore::try_acquire

counting_semaphore::try_acquire_for

counting_semaphore::try_acquire_until

常量

counting_semaphore::max

 

bool try_acquire() noexcept;		(C++20 起)

嘗試以原子方式減少內部計數器 1，如果它大於 ​0​；無論如何都不會發生阻塞。

返回值

如果它成功地將內部計數器減 1 則返回 true，否則返回 false。

注意

即使計數器大於 ​0​，實現也允許不減少計數器——即，它們允許虛假地失敗並返回 false。

參閱

release	增加內部計數器並解除阻塞獲取器 (公開成員函式)
acquire	遞減內部計數器或阻塞直到可以遞減 (公開成員函式)
try_acquire_for	嘗試遞減內部計數器，阻塞一段持續時間 (公開成員函式)
try_acquire_until	嘗試遞減內部計數器，阻塞直到某一時間點 (公開成員函式)