unique_lock() noexcept;
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(1) | (C++11 起) |
unique_lock( unique_lock&& other ) noexcept;
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(2) | (C++11 起) |
explicit unique_lock( mutex_type& m );
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(3) | (C++11 起) |
unique_lock( mutex_type& m, std::defer_lock_t t ) noexcept;
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(4) | (C++11 起) |
unique_lock( mutex_type& m, std::try_to_lock_t t );
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(5) | (C++11 起) |
unique_lock( mutex_type& m, std::adopt_lock_t t );
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(6) | (C++11 起) |
template< class Rep, class Period >
unique_lock( mutex_type& m, |
(7) | (C++11 起) |
template< class Clock, class Duration >
unique_lock( mutex_type& m, |
(8) | (C++11 起) |
构造 unique_lock
,可选地锁定提供的互斥。
unique_lock
。other
的内容初始化 unique_lock
。令 other
无关联互斥。m
为关联互斥的 unique_lock
。另外:m
。timeout_duration
或获得锁,之先到来者。可能阻塞长于 timeout_duration
。timeout_time
或获得锁,之先到来者。可能阻塞长于抵达 timeout_time
。other | - | 用以初始化状态的另一 unique_lock
|
m | - | 与锁关联且可选的获得所有权的互斥 |
t | - | 用于选择拥有不同锁定策略的构造函数的标签参数 |
timeout_duration | - | 要阻塞的最大时长 |
timeout_time | - | 要阻塞到的最大时间点 |
#include <iostream> #include <thread> #include <vector> #include <mutex> std::mutex m_a, m_b, m_c; int a, b, c = 1; void update() { { // 注意:可用 std::lock_guard 或 atomic<int> 代替 std::unique_lock<std::mutex> lk(m_a); a++; } { // 注意:细节和替代品见 std::lock 及 std::scoped_lock std::unique_lock<std::mutex> lk_b(m_b, std::defer_lock); std::unique_lock<std::mutex> lk_c(m_c, std::defer_lock); std::lock(lk_b, lk_c); b = std::exchange(c, b+c); } } int main() { std::vector<std::thread> threads; for (unsigned i = 0; i < 12; ++i) threads.emplace_back(update); for (auto& i: threads) i.join(); std::cout << a << "'th and " << a+1 << "'th Fibonacci numbers: " << b << " and " << c << '\n'; }
输出:
12'th and 13'th Fibonacci numbers: 144 and 233