RWLock Class Reference

A custom synchronization primitive for the Readers-Writers problem. More...

Collaboration diagram for RWLock:

Public Member Functions
void	lock_read ()
	Acquires a shared read lock.
void	unlock_read ()
	Releases the shared read lock.
void	lock_write ()
	Acquires an exclusive write lock.
void	unlock_write ()
	Releases the exclusive write lock.

Detailed Description

A custom synchronization primitive for the Readers-Writers problem.

• This class uses a single std::mutex and std::condition_variable to manage state. It implements a "Writer Preference" policy.

Definition at line 27 of file CustomRWLock.cpp.

Member Function Documentation

lock_read()

void RWLock::lock_read ( )

inline

Acquires a shared read lock.

• Blocks if:

1. A writer is currently active.
2. There are writers waiting in the queue (Starvation Protection).

Definition at line 43 of file CustomRWLock.cpp.

                     {
        std::unique_lock<std::mutex> lock(mtx);
        
        // Wait while a writer is active OR a writer is waiting
        while(writer_active || waiting_writers > 0) {
            cv.wait(lock);
        }
 
        active_readers++;
    }

Referenced by readerTask().

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lock_write()

void RWLock::lock_write ( )

inline

Acquires an exclusive write lock.

• Increments the waiting_writers count to block new readers. Blocks until all active readers and any active writer have finished.

Definition at line 72 of file CustomRWLock.cpp.

                      {
        std::unique_lock<std::mutex> lock(mtx);
        waiting_writers++;
 
        // Wait while any readers or writers are active
        while(active_readers > 0 || writer_active) {
            cv.wait(lock);
        }
 
        waiting_writers--;
        writer_active = true;
    }

Referenced by writerTask().

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unlock_read()

void RWLock::unlock_read ( )

inline

Releases the shared read lock.

• If this was the last active reader, it notifies all waiting threads (potentially waking a waiting writer).

Definition at line 59 of file CustomRWLock.cpp.

                       {
        std::unique_lock<std::mutex> lock(mtx);
        active_readers--;
        
        if(active_readers == 0)
            cv.notify_all();
    }

Referenced by readerTask().

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unlock_write()

void RWLock::unlock_write ( )

inline

Releases the exclusive write lock.

• Sets writer_active to false and wakes all waiting threads.

Definition at line 89 of file CustomRWLock.cpp.

                        {
        std::unique_lock<std::mutex> lock(mtx);
        writer_active = false;
        cv.notify_all();
    }

Referenced by writerTask().

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

• Readers-Writers/CustomRWLock.cpp