std::defer_lock, std::try_to_lock, std::adopt_lock

 

C++

语言

概念

实用工具库

字符串库

集装箱库

算法库

迭代器库

Numerics库

输入/输出库

本地化库

正则表达式库 （C++11）

原子操作库 （C++11）

线程的支持库 （C++11）

 

线程的支持库

主题 Original: Threads The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
thread （C++11）
this_thread命名空间 Original: this_thread namespace The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
get_id （C++11） yield （C++11）	sleep_for （C++11） sleep_until （C++11）
相互排斥 Original: Mutual exclusion The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
mutex （C++11） timed_mutex （C++11）	recursive_mutex （C++11） recursive_timed_mutex （C++11）
通用锁管理 Original: Generic lock management The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
lock_guard （C++11） unique_lock （C++11） defer_lock_t try_to_lock_t adopt_lock_t （C++11） （C++11） （C++11）	lock （C++11） try_lock （C++11） defer_lock try_to_lock adopt_lock （C++11） （C++11） （C++11）
条件变量 Original: Condition variables The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
condition_variable （C++11）
condition_variable_any （C++11）
notify_all_at_thread_exit （C++11）
cv_status （C++11）
期货 Original: Futures The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
promise （C++11） future （C++11） shared_future （C++11） packaged_task （C++11） async （C++11）	launch （C++11） future_status （C++11） future_error （C++11） future_category （C++11） future_errc （C++11）

 

constexpr std::defer_lock_t defer_lock = std::defer_lock_t();		（C++11 起）
constexpr std::try_to_lock_t try_to_lock = std::try_to_lock_t();		（C++11 起）
constexpr std::adopt_lock_t adopt_lock = std::adopt_lock_t();		（C++11 起）

std::defer_lock, std::try_to_lock and std::adopt_lock are instances of empty struct tag types std::defer_lock_t, std::try_to_lock_t and std::adopt_lock_t respectively.

They are used to specify locking strategies for std::lock_guard and std::unique_lock.

类型 Original: Type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.	Effect(s)
defer_lock_t	没有获得互斥体的所有权 Original: do not acquire ownership of the mutex The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
try_to_lock_t	不阻塞的情况下，试图获取互斥体的所有权 Original: try to acquire ownership of the mutex without blocking The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
adopt_lock_t	假设调用线程已经拥有互斥体的所有权 Original: assume the calling thread already has ownership of the mutex The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

。为例。

#include <mutex>
#include <thread>
 
struct bank_account {
    explicit bank_account(int balance) : balance(balance) {}
    int balance;
    std::mutex m;
};
 
void transfer(bank_account &from, bank_account &to, int amount)
{
    // attempt to lock both mutexes without deadlock
    std::lock(from.m, to.m);
 
    // make sure both already-locked mutexes are unlocked when 
    // we're done; if we just used the lock_guard without std::lock
    // and std::adopt_lock, we might deadlock with other calls to transfer
    std::lock_guard lock1(from.m, std::adopt_lock);
    std::lock_guard lock2(to.m, std::adopt_lock);
 
    from.balance -= amount;
    to.balance += amount;
}
 
int main()
{
    bank_account my_account(100);
    bank_account your_account(50);
 
    std::thread t1(transfer, my_account, your_account, 10);
    std::thread t2(transfer, your_account, my_account, 5);
 
    t1.join();
    t2.join();
}

。另请参阅。

defer_lock_t try_to_lock_t adopt_lock_t	标签类型用于指定锁定策略 Original: tag type used to specify locking strategy The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （类）
(constructor)	构建一个lock_guard，任意给定的互斥锁定 Original: constructs a lock_guard, optionally locking the given mutex The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （公共成员函数of std::lock_guard）
(constructor)	构建了一个unique_lock，可以提供的互斥锁 Original: constructs a unique_lock, optionally locking the supplied mutex The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （公共成员函数of std::unique_lock）