std::unique_lock<Mutex>::lock

 

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std::unique_lock

成员函数

unique_lock::unique_lock

unique_lock::~unique_lock

unique_lock::operator=

锁定

unique_lock::lock

unique_lock::try_lock

unique_lock::try_lock_for

unique_lock::try_lock_until

unique_lock::unlock

修改器

unique_lock::swap

unique_lock::release

观察器

unique_lock::mutex

unique_lock::owns_lock

unique_lock::operator bool

非成员函数

std::swap

 

void lock();		(C++11 起)

锁定关联互斥。等效地调用 mutex()->lock() 。

参数

（无）

返回值

（无）

异常

• 任何 mutex()->lock() 所抛的异常

• 若无关联互斥，则为以 std::errc::operation_not_permitted 为错误码的 std::system_error

• 若关联互斥已为此 unique_lock 所锁定（换言之， owns_lock 为 true ），则为以 std::errc::resource_deadlock_would_occur 为错误码的 std::system_error

示例

下列示例用 lock 重获得被解锁的互斥。

运行此代码

#include <mutex>
#include <thread>
#include <iostream>
#include <vector>
#include <chrono>
 
int main()
{
    int counter = 0;
    std::mutex counter_mutex;
    std::vector<std::thread> threads;
 
    auto worker_task = [&](int id) {
        std::unique_lock<std::mutex> lock(counter_mutex);
        ++counter;
        std::cout << id << ", initial counter: " << counter << '\n';
        lock.unlock();
 
        // 我们模拟昂贵操作时不保有锁
        std::this_thread::sleep_for(std::chrono::seconds(1));
 
        lock.lock();
        ++counter;
        std::cout << id << ", final counter: " << counter << '\n';
    };
 
    for (int i = 0; i < 10; ++i) threads.emplace_back(worker_task, i);
 
    for (auto &thread : threads) thread.join();
}

可能的输出：

0, initial counter: 1
1, initial counter: 2
2, initial counter: 3
3, initial counter: 4
4, initial counter: 5
5, initial counter: 6
6, initial counter: 7
7, initial counter: 8
8, initial counter: 9
9, initial counter: 10
6, final counter: 11
3, final counter: 12
4, final counter: 13
2, final counter: 14
5, final counter: 15
0, final counter: 16
1, final counter: 17
7, final counter: 18
9, final counter: 19
8, final counter: 20

参阅

try_lock	尝试锁定关联互斥，若互斥不可用则返回 (公开成员函数)
unlock	解锁关联互斥 (公开成员函数)