std::unique_lock<Mutex>::lock
来自cppreference.com
< cpp | thread | unique lock
| 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
| 尝试锁定关联互斥，若互斥不可用则返回 (公开成员函数) | |
| 解锁关联互斥 (公开成员函数) |