vpr::RWMutexPosix Class Reference

RWMutex wrapper for POSIX-compliant systems using pthreads rw mutex variables for the implementation. More...

#include <vpr/Sync/RWMutex.h>

List of all members.

Public Member Functions
	RWMutexPosix ()
	Constructor for vpr::RWMutexPosix class.
	~RWMutexPosix ()
	Destructor for vpr::RWMutexPosix class.
vpr::ReturnStatus	acquire ()
	Locks this mutex.
vpr::ReturnStatus	acquireRead ()
	Acquires a read mutex.
vpr::ReturnStatus	acquireWrite ()
	Acquire a write mutex.
vpr::ReturnStatus	tryAcquire ()
	Tries to acquire a lock on this mutex variable (does not block).
vpr::ReturnStatus	tryAcquireRead ()
	Tries to acquire a read mutex.
vpr::ReturnStatus	tryAcquireWrite ()
	Tries to acquire a write mutex.
vpr::ReturnStatus	release ()
	Releases the mutex.
int	test ()
	Tests the current lock status.
Protected Member Functions
void	operator= (const RWMutexPosix &)
	RWMutexPosix (const RWMutexPosix &)
Protected Attributes
pthread_rwlock_t	mRWMutex
	RWMutex variable for the class.
int	mLocked
	If true, then we are locked.

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Detailed Description

RWMutex wrapper for POSIX-compliant systems using pthreads rw mutex variables for the implementation.

This is typedef'd to vpr::RWMutex.

Definition at line 69 of file RWMutexPosix.h.

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Constructor & Destructor Documentation

vpr::RWMutexPosix::RWMutexPosix

(

)

[inline]

Constructor for vpr::RWMutexPosix class.

Postcondition:

The mutex variable is initialized for use. It must be initialized before any other member functions can do anything with it.

Definition at line 79 of file RWMutexPosix.h.

References mRWMutex.

                  : mLocked(0)
   {
      // Initialize the mutex.
      pthread_rwlock_init(&mRWMutex, NULL);
   }

vpr::RWMutexPosix::~RWMutexPosix

(

)

[inline]

Destructor for vpr::RWMutexPosix class.

Precondition:

The mutex variable should be unlocked before being destroyed, but if it is not, this routine will unlock it and then destroy it.

Postcondition:

The mutex variable is destroyed and unlocked if necessary.

Definition at line 93 of file RWMutexPosix.h.

References mRWMutex.

   {
      // Destroy the mutex.
      if ( pthread_rwlock_destroy(&mRWMutex) == -1 )
      {
         pthread_rwlock_unlock(&mRWMutex);
         pthread_rwlock_destroy(&mRWMutex);
      }
   }

vpr::RWMutexPosix::RWMutexPosix

(

const RWMutexPosix &

)

[inline, protected]

Definition at line 305 of file RWMutexPosix.h.

{;}

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Member Function Documentation

vpr::ReturnStatus vpr::RWMutexPosix::acquire

(

)

[inline]

Locks this mutex.

Postcondition:

A lock on the mutex variable is acquired by the caller. If a lock has already been acquired by another process/thread, the caller blocks until the mutex has been freed.

Returns:

vpr::ReturnStatus::Succeed is returned if the lock is acquired.

vpr::ReturnStatus::Fail is returned if an error occurred.

Note:

Acquires the write lock.

Definition at line 115 of file RWMutexPosix.h.

References acquireWrite().

   { 
      return acquireWrite();
   }

vpr::ReturnStatus vpr::RWMutex::acquireRead

(

)

[inline]

Acquires a read mutex.

Precondition:

None.

Postcondition:

A lock on the mutex variable is acquired by the caller. If a lock has already been acquired by another process/thread, the caller blocks until the mutex has been freed.

Returns:

vpr::ReturnStatus::Succeed is returned if the lock is acquired.

vpr::ReturnStatus::Fail is returned if an error occurred.

Definition at line 131 of file RWMutexPosix.h.

References vpr::ReturnStatus::Fail, mLocked, and mRWMutex.

Referenced by vpr::ReadGuard::acquire().

   {
      int retval = pthread_rwlock_rdlock(&mRWMutex);

      // Locking succeeded.
      if ( retval == 0 )
      {
         mLocked = 1;
         return vpr::ReturnStatus();
      }
#ifdef _DEBUG
      // This thread tried to lock the mutex twice and a deadlock condition
      // was reported.
      else if ( retval == EDEADLK )
      {
         perror("Tried to lock mutex twice (RWMutexPosix.h:146)");
         return vpr::ReturnStatus(vpr::ReturnStatus::Fail);
      }
#endif
      // Some other error occurred.
      else
      {
         return vpr::ReturnStatus(vpr::ReturnStatus::Fail);
      }
   }

vpr::ReturnStatus vpr::RWMutex::acquireWrite

(

)

[inline]

Acquire a write mutex.

Postcondition:

A lock on the mutex variable is acquired by the caller. If a lock has already been acquired by another process/thread, the caller blocks until the mutex has been freed.

Returns:

vpr::ReturnStatus::Succeed is returned if the lock is acquired.

vpr::ReturnStatus::Fail is returned if an error occurred.

Definition at line 167 of file RWMutexPosix.h.

References vpr::ReturnStatus::Fail, mLocked, and mRWMutex.

Referenced by acquire(), and vpr::WriteGuard::acquire().

   {
      int retval = pthread_rwlock_wrlock(&mRWMutex);

      // Locking succeeded.
      if ( retval == 0 )
      {
         mLocked = 1;
         return vpr::ReturnStatus();
      }
#ifdef _DEBUG
      // This thread tried to lock the mutex twice and a deadlock condition
      // was reported.
      else if ( retval == EDEADLK )
      {
         perror("Tried to lock mutex twice (RWMutexPosix.h:184)");
         return vpr::ReturnStatus(vpr::ReturnStatus::Fail);
      }
#endif
      // Some other error occurred.
      else
      {
         return vpr::ReturnStatus(vpr::ReturnStatus::Fail);
      }
   }

vpr::ReturnStatus vpr::RWMutexPosix::tryAcquire

(

)

[inline]

Tries to acquire a lock on this mutex variable (does not block).

Postcondition:

A lock on the mutex variable is acquired by the caller. If a lock has already been acquired by another process/thread, the caller returns does not wait for it to be unlocked.

Returns:

vpr::ReturnStatus::Succeed is returned if the lock is acquired.

vpr::ReturnStatus::Fail is returned if the mutex is already locked.

Note:

Tries to acquire the write mutex.

Definition at line 206 of file RWMutexPosix.h.

References tryAcquireWrite().

   {
      return tryAcquireWrite();
   }

vpr::ReturnStatus vpr::RWMutex::tryAcquireRead

(

)

[inline]

Tries to acquire a read mutex.

Postcondition:

A lock on the mutex variable is acquired by the caller. If a lock has already been acquired by another process/thread, the caller returns does not wait for it to be unlocked.

Returns:

vpr::ReturnStatus::Succeed is returned if the read lock is acquired.

vpr::ReturnStatus::Fail is returned if the mutex is already locked.

Definition at line 223 of file RWMutexPosix.h.

References vpr::ReturnStatus::Fail, mLocked, and mRWMutex.

Referenced by vpr::ReadGuard::tryAcquire().

   {
      if ( pthread_rwlock_tryrdlock(&mRWMutex) == 0 )
      {
         mLocked = 1;
         return vpr::ReturnStatus();
      }
      else
      {
         return vpr::ReturnStatus(vpr::ReturnStatus::Fail);
      }

   }

vpr::ReturnStatus vpr::RWMutex::tryAcquireWrite

(

)

[inline]

Tries to acquire a write mutex.

Postcondition:

A lock on the mutex variable is acquired by the caller. If a lock has already been acquired by another process/thread, the caller returns does not wait for it to be unlocked.

Returns:

vpr::ReturnStatus::Succeed is returned if the write lock is acquired.

vpr::ReturnStatus::Fail is returned if the mutex is already locked.

Definition at line 249 of file RWMutexPosix.h.

References vpr::ReturnStatus::Fail, mLocked, and mRWMutex.

Referenced by tryAcquire(), and vpr::WriteGuard::tryAcquire().

   {
      if ( pthread_rwlock_trywrlock(&mRWMutex) == 0 )
      {
         mLocked = 1;
         return vpr::ReturnStatus();
      }
      else
      {
         return vpr::ReturnStatus(vpr::ReturnStatus::Fail);
      }

   }

vpr::ReturnStatus vpr::RWMutex::release

(

)

[inline]

Releases the mutex.

Precondition:

The mutex variable must be locked.

Postcondition:

The mutex variable is unlocked.

Returns:

vpr::ReturnStatus::Succeed is returned if the lock is released successfully.

vpr::ReturnStatus::Fail is returned otherwise.

Definition at line 273 of file RWMutexPosix.h.

References vpr::ReturnStatus::Fail, mLocked, and mRWMutex.

Referenced by vpr::WriteGuard::release(), vpr::ReadGuard::release(), vpr::ReadGuard::~ReadGuard(), and vpr::WriteGuard::~WriteGuard().

   {
      mLocked = 0;
      if ( pthread_rwlock_unlock(&mRWMutex) == 0 )
      {
         return vpr::ReturnStatus();
      }
      else
      {
         return vpr::ReturnStatus(vpr::ReturnStatus::Fail);
      }
   }

int vpr::RWMutexPosix::test

(

)

[inline]

Tests the current lock status.

Postcondition:

The state of the mutex variable is returned.

Returns:

0 is returned if this mutex is not currently locked.

1 is returned if this mutex is locked.

Definition at line 294 of file RWMutexPosix.h.

References mLocked.

   {
      return mLocked;
   }

void vpr::RWMutexPosix::operator=

(

const RWMutexPosix &

)

[inline, protected]

Definition at line 304 of file RWMutexPosix.h.

{;}

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Member Data Documentation

pthread_rwlock_t vpr::RWMutexPosix::mRWMutex [protected]

RWMutex variable for the class.

Definition at line 300 of file RWMutexPosix.h.

Referenced by acquireRead(), acquireWrite(), release(), RWMutexPosix(), tryAcquireRead(), tryAcquireWrite(), and ~RWMutexPosix().

int vpr::RWMutexPosix::mLocked [protected]

If true, then we are locked.

Definition at line 301 of file RWMutexPosix.h.

Referenced by acquireRead(), acquireWrite(), release(), test(), tryAcquireRead(), and tryAcquireWrite().

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

• RWMutexPosix.h
• RWMutex.cpp

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