ACE_File_Lock Class Reference

A wrapper around the UNIX file locking mechanism. More...

#include <File_Lock.h>

Collaboration diagram for ACE_File_Lock:

Public Member Functions
	ACE_File_Lock (ACE_HANDLE handle=ACE_INVALID_HANDLE, bool unlink_in_destructor=true)
	ACE_File_Lock (const ACE_TCHAR *filename, int flags, mode_t mode=0, bool unlink_in_destructor=true)
int	open (const ACE_TCHAR *filename, int flags, mode_t mode=0)
	~ACE_File_Lock ()
	Remove a File lock by releasing it and closing down the <handle_>.
int	remove (bool unlink_file=true)
int	acquire (short whence=0, ACE_OFF_T start=0, ACE_OFF_T len=1)
int	tryacquire (short whence=0, ACE_OFF_T start=0, ACE_OFF_T len=1)
int	release (short whence=0, ACE_OFF_T start=0, ACE_OFF_T len=1)
	Unlock a readers/writer lock.
int	acquire_write (short whence=0, ACE_OFF_T start=0, ACE_OFF_T len=1)
int	tryacquire_write (short whence=0, ACE_OFF_T start=0, ACE_OFF_T len=1)
int	tryacquire_write_upgrade (short whence=0, ACE_OFF_T start=0, ACE_OFF_T len=1)
int	acquire_read (short whence=0, ACE_OFF_T start=0, ACE_OFF_T len=1)
int	tryacquire_read (short whence=0, ACE_OFF_T start=0, ACE_OFF_T len=1)
ACE_HANDLE	get_handle () const
	Get underlying ACE_HANDLE for the file.
void	set_handle (ACE_HANDLE)
void	dump () const
	Dump state of the object.

Public Attributes
	ACE_ALLOC_HOOK_DECLARE
	Declare the dynamic allocation hooks.

Protected Attributes
ACE_OS::ace_flock_t	lock_
	Locking structure for OS record locks.
bool	removed_
bool const	unlink_in_destructor_

Private Member Functions
void	operator= (const ACE_File_Lock &)=delete
	ACE_File_Lock (const ACE_File_Lock &)=delete

Detailed Description

A wrapper around the UNIX file locking mechanism.

Allows us to "adapt" the UNIX file locking mechanisms to work with all of our Guard stuff...

Constructor & Destructor Documentation

ACE_File_Lock() [1/3]

ACE_File_Lock::ACE_File_Lock	(	ACE_HANDLE	handle = ACE_INVALID_HANDLE,
		bool	unlink_in_destructor = true )

Set the <handle_> of the File_Lock to handle. Note that this constructor assumes ownership of the handle and will close it down in <remove>. If you want the handle to stay open when <remove> is called make sure to call <dup> on the handle. If you don't want the file unlinked in the destructor pass a zero value for <unlink_in_destructor>.

ACE_File_Lock() [2/3]

ACE_File_Lock::ACE_File_Lock	(	const ACE_TCHAR *	filename,
		int	flags,
		mode_t	mode = 0,
		bool	unlink_in_destructor = true )

Open the filename with flags and mode and set the result to <handle_>. If you don't want the file unlinked in the destructor pass a false value for unlink_in_destructor.

~ACE_File_Lock()

ACE_File_Lock::~ACE_File_Lock

(

)

Remove a File lock by releasing it and closing down the <handle_>.

ACE_File_Lock() [3/3]

ACE_File_Lock::ACE_File_Lock ( const ACE_File_Lock & )

privatedelete

Member Function Documentation

acquire()

int ACE_File_Lock::acquire ( short whence = 0, ACE_OFF_T start = 0, ACE_OFF_T len = 1 )

inline

Note, for interface uniformity with other synchronization wrappers we include the acquire() method. This is implemented as a write-lock to be on the safe-side...

acquire_read()

int ACE_File_Lock::acquire_read ( short whence = 0, ACE_OFF_T start = 0, ACE_OFF_T len = 1 )

inline

Acquire a read lock, but block if a writer hold the lock. Returns -1 on failure. If we "failed" because someone else already had the lock, errno is set to EBUSY.

acquire_write()

int ACE_File_Lock::acquire_write ( short whence = 0, ACE_OFF_T start = 0, ACE_OFF_T len = 1 )

inline

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

dump()

void ACE_File_Lock::dump

(

)

const

Dump state of the object.

get_handle()

ACE_HANDLE ACE_File_Lock::get_handle ( ) const

inline

Get underlying ACE_HANDLE for the file.

open()

int ACE_File_Lock::open	(	const ACE_TCHAR *	filename,
		int	flags,
		mode_t	mode = 0 )

Open the filename with flags and mode and set the result to <handle_>.

operator=()

void ACE_File_Lock::operator= ( const ACE_File_Lock & )

privatedelete

release()

int ACE_File_Lock::release ( short whence = 0, ACE_OFF_T start = 0, ACE_OFF_T len = 1 )

inline

Unlock a readers/writer lock.

remove()

int ACE_File_Lock::remove ( bool unlink_file = true )

inline

Remove a File lock by releasing it and closing down the <handle_>. If unlink_file is true then we unlink the file.

set_handle()

void ACE_File_Lock::set_handle ( ACE_HANDLE h )

inline

Set underlying ACE_HANDLE. Note that this method assumes ownership of the handle and will close it down in <remove>. If you want the handle to stay open when <remove> is called make sure to call <dup> on the handle before closing it. You are responsible for the closing the existing handle before overwriting it.

tryacquire()

int ACE_File_Lock::tryacquire ( short whence = 0, ACE_OFF_T start = 0, ACE_OFF_T len = 1 )

inline

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

tryacquire_read()

int ACE_File_Lock::tryacquire_read ( short whence = 0, ACE_OFF_T start = 0, ACE_OFF_T len = 1 )

inline

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.

tryacquire_write()

int ACE_File_Lock::tryacquire_write ( short whence = 0, ACE_OFF_T start = 0, ACE_OFF_T len = 1 )

inline

Conditionally acquire a write 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.

tryacquire_write_upgrade()

int ACE_File_Lock::tryacquire_write_upgrade ( short whence = 0, ACE_OFF_T start = 0, ACE_OFF_T len = 1 )

inline

Conditionally upgrade to a write 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.

Member Data Documentation

ACE_ALLOC_HOOK_DECLARE

ACE_File_Lock::ACE_ALLOC_HOOK_DECLARE

Declare the dynamic allocation hooks.

lock_

ACE_OS::ace_flock_t ACE_File_Lock::lock_

protected

Locking structure for OS record locks.

removed_

bool ACE_File_Lock::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...

unlink_in_destructor_

bool const ACE_File_Lock::unlink_in_destructor_

protected

Keeps track of whether to unlink the underlying file in the destructor.

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

• File_Lock.h
• File_Lock.cpp
• File_Lock.inl