ACE_RW_Mutex Class Reference

Wrapper for readers/writer locks. More...

#include <RW_Mutex.h>

Inheritance diagram for ACE_RW_Mutex:

[legend]

List of all members.

Public Member Functions
	ACE_RW_Mutex (int type=USYNC_THREAD, const ACE_TCHAR *name=0, void *arg=0)
	Initialize a readers/writer lock.
	~ACE_RW_Mutex (void)
	Implicitly destroy a readers/writer lock.
int	remove (void)
int	acquire_read (void)
	Acquire a read lock, but block if a writer hold the lock.
int	acquire_write (void)
int	tryacquire_read (void)
int	tryacquire_write (void)
	Conditionally acquire a write lock (i.e., won't block).
int	tryacquire_write_upgrade (void)
int	acquire (void)
int	tryacquire (void)
int	release (void)
	Unlock a readers/writer lock.
const ACE_rwlock_t &	lock (void) const
	Return the underlying lock.
void	dump (void) const
	Dump the state of an object.
Public Attributes
	ACE_ALLOC_HOOK_DECLARE
	Declare the dynamic allocation hooks.
Protected Attributes
ACE_rwlock_t	lock_
	Readers/writer lock.
bool	removed_
Private Member Functions
void	operator= (const ACE_RW_Mutex &)
	ACE_RW_Mutex (const ACE_RW_Mutex &)

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Detailed Description

Wrapper for readers/writer locks.

These are most useful for applications that have many more parallel readers than writers...

Definition at line 41 of file RW_Mutex.h.

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Constructor & Destructor Documentation

ACE_RW_Mutex::ACE_RW_Mutex	(	int	type = USYNC_THREAD,
		const ACE_TCHAR *	name = 0,
		void *	arg = 0
	)

Initialize a readers/writer lock.

ACE_RW_Mutex::~ACE_RW_Mutex

(

void

)

Implicitly destroy a readers/writer lock.

ACE_RW_Mutex::ACE_RW_Mutex

(

const ACE_RW_Mutex &

)

[private]

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Member Function Documentation

int ACE_RW_Mutex::acquire

(

void

)

Note, for interface uniformity with other synchronization wrappers we include the <acquire> method. This is implemented as a write-lock to safe...

Definition at line 42 of file RW_Mutex.inl.

{
// ACE_TRACE ("ACE_RW_Mutex::acquire");
  return ACE_OS::rw_wrlock (&this->lock_);
}

int ACE_RW_Mutex::acquire_read

(

void

)

Acquire a read lock, but block if a writer hold the lock.

Definition at line 28 of file RW_Mutex.inl.

{
// ACE_TRACE ("ACE_RW_Mutex::acquire_read");
  return ACE_OS::rw_rdlock (&this->lock_);
}

int ACE_RW_Mutex::acquire_write

(

void

)

Acquire a write lock, but block if any readers or a writer hold the lock.

Definition at line 35 of file RW_Mutex.inl.

{
// ACE_TRACE ("ACE_RW_Mutex::acquire_write");
  return ACE_OS::rw_wrlock (&this->lock_);
}

void ACE_RW_Mutex::dump

(

void

)

const

Dump the state of an object.

Reimplemented in ACE_RW_Thread_Mutex.

const ACE_rwlock_t & ACE_RW_Mutex::lock

(

void

)

const

Return the underlying lock.

Definition at line 8 of file RW_Mutex.inl.

{
// ACE_TRACE ("ACE_RW_Mutex::lock");
  return this->lock_;
}

void ACE_RW_Mutex::operator=

(

const ACE_RW_Mutex &

)

[private]

int ACE_RW_Mutex::release

(

void

)

Unlock a readers/writer lock.

Definition at line 77 of file RW_Mutex.inl.

{
// ACE_TRACE ("ACE_RW_Mutex::release");
  return ACE_OS::rw_unlock (&this->lock_);
}

int ACE_RW_Mutex::remove

(

void

)

Explicitly destroy a readers/writer lock. Note that only one thread should call this method since it doesn't protect against race conditions.

Definition at line 15 of file RW_Mutex.inl.

{
// ACE_TRACE ("ACE_RW_Mutex::remove");
  int result = 0;
  if (!this->removed_)
    {
      this->removed_ = true;
      result = ACE_OS::rwlock_destroy (&this->lock_);
    }
  return result;
}

int ACE_RW_Mutex::tryacquire

(

void

)

Note, for interface uniformity with other synchronization wrappers we include the <tryacquire> method. This is implemented as a write-lock to be safe... Returns -1 on failure. If we "failed" because someone else already had the lock, errno is set to EBUSY.

Definition at line 70 of file RW_Mutex.inl.

{
// ACE_TRACE ("ACE_RW_Mutex::tryacquire");
  return this->tryacquire_write ();
}

int ACE_RW_Mutex::tryacquire_read

(

void

)

Conditionally acquire a read lock (i.e., won't block). Returns -1 on failure. If we "failed" because someone else already had the lock, errno is set to EBUSY.

Definition at line 49 of file RW_Mutex.inl.

{
// ACE_TRACE ("ACE_RW_Mutex::tryacquire_read");
  return ACE_OS::rw_tryrdlock (&this->lock_);
}

int ACE_RW_Mutex::tryacquire_write

(

void

)

Conditionally acquire a write lock (i.e., won't block).

Definition at line 56 of file RW_Mutex.inl.

{
// ACE_TRACE ("ACE_RW_Mutex::tryacquire_write");
  return ACE_OS::rw_trywrlock (&this->lock_);
}

int ACE_RW_Mutex::tryacquire_write_upgrade

(

void

)

Conditionally upgrade a read lock to a write lock. This only works if there are no other readers present, in which case the method returns 0. Otherwise, the method returns -1 and sets errno to EBUSY. Note that the caller of this method *must* already possess this lock as a read lock (but this condition is not checked by the current implementation).

Reimplemented in ACE_RW_Thread_Mutex.

Definition at line 63 of file RW_Mutex.inl.

{
// ACE_TRACE ("ACE_RW_Mutex::tryacquire_write_upgrade");
  return ACE_OS::rw_trywrlock_upgrade (&this->lock_);
}

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Member Data Documentation

ACE_RW_Mutex::ACE_ALLOC_HOOK_DECLARE

Declare the dynamic allocation hooks.

Reimplemented in ACE_RW_Thread_Mutex.

Definition at line 112 of file RW_Mutex.h.

ACE_rwlock_t ACE_RW_Mutex::lock_ [protected]

Readers/writer lock.

Definition at line 116 of file RW_Mutex.h.

bool ACE_RW_Mutex::removed_ [protected]

Keeps track of whether <remove> has been called yet to avoid multiple <remove> calls, e.g., explicitly and implicitly in the destructor. This flag isn't protected by a lock, so make sure that you don't have multiple threads simultaneously calling <remove> on the same object, which is a bad idea anyway...

Definition at line 123 of file RW_Mutex.h.

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

• RW_Mutex.h
• RW_Mutex.inl