ACE_RW_Process_Mutex Class Reference

Wrapper for readers/writer locks that exist across processes. More...

#include <RW_Process_Mutex.h>

Collaboration diagram for ACE_RW_Process_Mutex:

Public Member Functions
	ACE_RW_Process_Mutex (const ACE_TCHAR *name=0, int flags=O_CREAT|O_RDWR, mode_t mode=ACE_DEFAULT_RW_PROCESS_MUTEX_PERMS)
	~ACE_RW_Process_Mutex ()
int	remove ()
int	acquire ()
int	tryacquire ()
int	release ()
	Release lock.
int	acquire_read ()
int	acquire_write ()
int	tryacquire_read ()
int	tryacquire_write ()
int	tryacquire_write_upgrade ()
const ACE_File_Lock &	lock () const
	Return the underlying lock.
void	dump () const
	Dump the state of an object.

Public Attributes
	ACE_ALLOC_HOOK_DECLARE
	Declare the dynamic allocation hooks.

Private Member Functions
const ACE_TCHAR *	unique_name ()
	Create and return the unique name.

Private Attributes
ACE_TCHAR	name_ [ACE_UNIQUE_NAME_LEN]
ACE_File_Lock	lock_
	We need this to get the readers/writer semantics...

Detailed Description

Wrapper for readers/writer locks that exist across processes.

Note

This class uses an ACE_File_Lock as its implementation. Thus, it can only be reliably used between separate processes, rather than threads in the same process. This isn't a limitation of ACE, it's simply the file lock semantics on UNIX and Win32.

Todo

For systems with pthread_rwlockattr_setpshared one may consider using them to make the mutex faster.

Constructor & Destructor Documentation

ACE_RW_Process_Mutex()

ACE_RW_Process_Mutex::ACE_RW_Process_Mutex	(	const ACE_TCHAR *	name = 0,
		int	flags = O_CREAT|O_RDWR,
		mode_t	mode = ACE_DEFAULT_RW_PROCESS_MUTEX_PERMS )

Create a cross-process readers/writer mutex, passing in the optional name, flags and mode

See also

ACE_File_Lock. If not specified, a name is generated and flags and mode are set to default platform values.

~ACE_RW_Process_Mutex()

ACE_RW_Process_Mutex::~ACE_RW_Process_Mutex

(

)

Member Function Documentation

acquire()

int ACE_RW_Process_Mutex::acquire ( )

inline

Same as acquire_write(). Acquire lock ownership; blocks until the lock is acquired or the operation fails.

acquire_read()

int ACE_RW_Process_Mutex::acquire_read ( )

inline

Acquire read lock; blocks until the lock is acquired or the operation fails.

acquire_write()

int ACE_RW_Process_Mutex::acquire_write ( )

inline

Acquire write lock; blocks until the lock is acquired or the operation fails.

dump()

void ACE_RW_Process_Mutex::dump

(

)

const

Dump the state of an object.

lock()

const ACE_File_Lock & ACE_RW_Process_Mutex::lock ( ) const

inline

Return the underlying lock.

release()

int ACE_RW_Process_Mutex::release ( )

inline

Release lock.

remove()

int ACE_RW_Process_Mutex::remove ( )

inline

Explicitly destroy the mutex. Note that only one thread should call this method since it doesn't protect against race conditions.

tryacquire()

int ACE_RW_Process_Mutex::tryacquire ( )

inline

Same as tryacquire_write(). Try to acquire the lock, but do not block if the lock is not immediately acquired.

Return values

-1	on failure. If the lock is already held, errno is set to EBUSY.

tryacquire_read()

int ACE_RW_Process_Mutex::tryacquire_read ( )

inline

Try to acquire the read lock, but do not block if the lock is not immediately acquired.

Return values

-1	on failure. If the lock is already held, errno is set to EBUSY.

tryacquire_write()

int ACE_RW_Process_Mutex::tryacquire_write ( )

inline

Try to acquire the write lock, but do not block if the lock is not immediately acquired.

Return values

-1	on failure. If the lock is already held, errno is set to EBUSY.

tryacquire_write_upgrade()

int ACE_RW_Process_Mutex::tryacquire_write_upgrade ( )

inline

Attempt to upgrade a read lock to a write lock. Returns 0 on success, -1 on failure.

unique_name()

const ACE_TCHAR * ACE_RW_Process_Mutex::unique_name ( )

private

Create and return the unique name.

Member Data Documentation

ACE_ALLOC_HOOK_DECLARE

ACE_RW_Process_Mutex::ACE_ALLOC_HOOK_DECLARE

Declare the dynamic allocation hooks.

lock_

ACE_File_Lock ACE_RW_Process_Mutex::lock_

private

We need this to get the readers/writer semantics...

name_

ACE_TCHAR ACE_RW_Process_Mutex::name_[ACE_UNIQUE_NAME_LEN]

private

If the user does not provide a name we generate a unique name in this buffer.

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

• RW_Process_Mutex.h
• RW_Process_Mutex.cpp
• RW_Process_Mutex.inl