engine::Mutex Class Reference

#include <userver/engine/mutex.hpp>

Detailed Description

std::mutex replacement for asynchronous tasks.

Ignores task cancellations (succeeds even if the current task is cancelled).

Example usage:

    engine::Mutex mutex;
    constexpr std::string_view kTestData = "Test Data";
 
    {
        std::lock_guard<engine::Mutex> lock(mutex);
        // accessing data under a mutex
        const auto x = kTestData;
        ASSERT_EQ(kTestData, x);
    }

See also

Synchronization Primitives

Definition at line 28 of file mutex.hpp.

Public Member Functions
	Mutex (const Mutex &)=delete
	Mutex (Mutex &&)=delete
Mutex &	operator= (const Mutex &)=delete
Mutex &	operator= (Mutex &&)=delete
void	lock ()
void	unlock ()
bool	try_lock () noexcept
template<typename Rep, typename Period>
bool	try_lock_for (const std::chrono::duration< Rep, Period > &)
template<typename Clock, typename Duration>
bool	try_lock_until (const std::chrono::time_point< Clock, Duration > &)
bool	try_lock_until (Deadline deadline)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Member Function Documentation

lock()

void engine::Mutex::lock

(

)

Locks the mutex. Blocks current coroutine if the mutex is locked by another coroutine. Throws if a coroutine tries to lock a mutex which is already locked by the current coroutine.

Note

The method waits for the mutex even if the current task is cancelled.

try_lock()

bool engine::Mutex::try_lock ( )

nodiscardnoexcept

Tries to lock the mutex without blocking the coroutine, returns true if succeeded.

Note

The behavior of the function is not affected by the cancellation requests.

try_lock_for()

template<typename Rep, typename Period>

bool engine::Mutex::try_lock_for ( const std::chrono::duration< Rep, Period > & duration )

nodiscard

Tries to lock the mutex in specified duration. Blocks current coroutine if the mutex is locked by another coroutine up to the provided duration. Throws if a coroutine tries to lock a mutex which is already locked by the current coroutine.

Returns

true if the locking succeeded

Note

The method waits for the mutex even if the current task is cancelled.

Definition at line 94 of file mutex.hpp.

try_lock_until()

template<typename Clock, typename Duration>

bool engine::Mutex::try_lock_until ( const std::chrono::time_point< Clock, Duration > & until )

nodiscard

Tries to lock the mutex till specified time point. Blocks current coroutine if the mutex is locked by another coroutine up to the provided time point. Throws if a coroutine tries to lock a mutex which is already locked by the current coroutine.

Returns

true if the locking succeeded

Note

The method waits for the mutex even if the current task is cancelled.

Definition at line 99 of file mutex.hpp.

unlock()

void engine::Mutex::unlock

(

)

Unlocks the mutex. Before calling this method the mutex should be locked by the current coroutine.

Note

the order of coroutines to unblock is unspecified. Any code assuming any specific order (e.g. FIFO) is incorrect and should be fixed.

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The documentation for this class was generated from the following file:

• userver/engine/mutex.hpp