samchon::library::SharedReadLock Class Reference

Shared lock from a RWMutex. More...

#include <SharedReadLock.hpp>

Collaboration diagram for samchon::library::SharedReadLock:

Public Member Functions
	SharedReadLock (const RWMutex &, bool=true)
	Construct from RWMutex. More...
	SharedReadLock (const SharedReadLock &)
	Copy Constructor. More...
	SharedReadLock (SharedReadLock &&)
	Move Constructor. More...
	~SharedReadLock ()
	Default Destructor. More...
void	lock () const
	Lock on read. More...
void	unlock () const
	Unlock of read. More...

Private Attributes
const RWMutex *	semaphore
	Managed RWMutex. More...
std::atomic< size_t > *	reference
	Referencing count sharing same RWMutex. More...
std::atomic< bool > *	isLocked
	Whether the mutex was locked by SharedReadLock. More...

Detailed Description

Shared lock from a RWMutex.

A SharedReadLock is an object manages a RWMutex with shared ownership in both states.

• locked
• unlocked

On default construction, the object acquires a RWMutex object, for whose locking and unlocking operations becomes responsible. When copy constructions, responsibilities of locking and unlocking RWMutex are shared with copied with those SharedReadLock objects.

The class shared_lock is a general-purpose shared mutex ownership wrapper allowing deferred locking, timed locking and transfer of lock ownership. Locking a shared_lock locks the associated shared mutex in shared mode (to lock it in exclusive mode, std::unique_lock can be used)

This class guarantees a unlocked status on destruction of all shared objects (even if not called explicitly). Therefore it is especially useful as an object with automatic duration, as it guarantees the RWMutex object is properly unlocked in case an exception is thrown.

Referenced comments of std::unique_lock

• http://www.cplusplus.com/reference/mutex/unique_lock/

Note

Though, that the SharedReadLock object does not manage the lifetime of the RWMutex object in any way: the duration of the RWMutex object shall extend at least until the destruction of the SharedReadLock that manages it.

See also

library::UniqueAcquire

samchon::library

Author

Jeongho Nam http://samchon.org

Definition at line 50 of file SharedReadLock.hpp.

Constructor & Destructor Documentation

SharedReadLock::SharedReadLock	(	const RWMutex &	semaphore,
		bool	doLock = true
	)

Construct from RWMutex.

Parameters

semaphore	RWMutex to manage
doLock	Whether to lock directly or not

Definition at line 12 of file SharedReadLock.cpp.

References samchon::library::RWMutex::readLock().

Here is the call graph for this function:

SharedReadLock::SharedReadLock

(

const SharedReadLock &

obj

)

Copy Constructor.

Definition at line 22 of file SharedReadLock.cpp.

References isLocked, reference, and semaphore.

SharedReadLock::SharedReadLock

(

SharedReadLock &&

obj

)

Move Constructor.

Definition at line 30 of file SharedReadLock.cpp.

SharedReadLock::~SharedReadLock

(

)

Default Destructor.

Definition at line 43 of file SharedReadLock.cpp.

Member Function Documentation

void SharedReadLock::lock

(

)

const

Lock on read.

Increases a reading count.

When write_lock is on a progress, wait until write_unlock to be called.

• Reading can be done by multiple sections.
• Reading can't be done when writing.

Warning

You've to call read_unlock when the reading work is terminated.

Definition at line 58 of file SharedReadLock.cpp.

void SharedReadLock::unlock

(

)

const

Unlock of read.

Decreases a reading count.

When write_lock had done after read_lock, it continues by read_unlock if the reading count was 1 (read_unlock makes the count to be zero).

Definition at line 66 of file SharedReadLock.cpp.

Member Data Documentation

const RWMutex* samchon::library::SharedReadLock::semaphore

private

Managed RWMutex.

Definition at line 56 of file SharedReadLock.hpp.

Referenced by SharedReadLock().

std::atomic<size_t>* samchon::library::SharedReadLock::reference

private

Referencing count sharing same RWMutex.

Definition at line 61 of file SharedReadLock.hpp.

Referenced by SharedReadLock().

std::atomic<bool>* samchon::library::SharedReadLock::isLocked

private

Whether the mutex was locked by SharedReadLock.

Definition at line 66 of file SharedReadLock.hpp.

Referenced by SharedReadLock().

---

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

• D:/OneDrive/Project/Samchon/framework/cpp/samchon/library/SharedReadLock.hpp
• D:/OneDrive/Project/Samchon/framework/cpp/samchon/library/SharedReadLock.cpp