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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:

Collaboration graph
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List of all members.

Public Member Functions

 ACE_RW_Process_Mutex (const ACE_TCHAR *name=0, int flags=O_CREAT|O_RDWR, mode_t mode=ACE_DEFAULT_OPEN_PERMS)
 ~ACE_RW_Process_Mutex (void)
int remove (void)
int acquire (void)
 Acquire lock ownership (wait on queue if necessary).

int tryacquire (void)
int release (void)
 Release lock and unblock a thread at head of queue.

int acquire_read (void)
 Acquire lock ownership (wait on queue if necessary).

int acquire_write (void)
 Acquire lock ownership (wait on queue if necessary).

int tryacquire_read (void)
int tryacquire_write (void)
int tryacquire_write_upgrade (void)
const ACE_File_Lock & 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.


Private Member Functions

const ACE_TCHAR * unique_name (void)
 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 that because this class uses the as its implementation it only can 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.

Definition at line 42 of file RW_Process_Mutex.h.

Constructor & Destructor Documentation

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

Create a readers/writer , passing in the optional name, and

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

Definition at line 30 of file RW_Process_Mutex.cpp.

References ACE_TCHAR, and mode_t. 

00033   : lock_ (name ? name : unique_name (), flags, mode)
00034 {
00035 // ACE_TRACE ("ACE_RW_Process_Mutex::ACE_RW_Process_Mutex");
00036 }

ACE_RW_Process_Mutex::~ACE_RW_Process_Mutex (  void   ) 
 

Definition at line 38 of file RW_Process_Mutex.cpp. 

00039 {
00040 // ACE_TRACE ("ACE_RW_Process_Mutex::~ACE_RW_Process_Mutex");
00041 }

Member Function Documentation

ACE_INLINE int ACE_RW_Process_Mutex::acquire (  void   ) 
 

Acquire lock ownership (wait on queue if necessary).

Definition at line 16 of file RW_Process_Mutex.inl.

References ACE_File_Lock::acquire(). 

00017 {
00018   return this->lock_.acquire ();
00019 }

ACE_INLINE int ACE_RW_Process_Mutex::acquire_read (  void   ) 
 

Acquire lock ownership (wait on queue if necessary).

Definition at line 37 of file RW_Process_Mutex.inl.

References ACE_File_Lock::acquire_read(). 

00038 {
00039   return this->lock_.acquire_read ();
00040 }

ACE_INLINE int ACE_RW_Process_Mutex::acquire_write (  void   ) 
 

Acquire lock ownership (wait on queue if necessary).

Definition at line 44 of file RW_Process_Mutex.inl.

References ACE_File_Lock::acquire_write(). 

00045 {
00046   return this->lock_.acquire_write ();
00047 }

void ACE_RW_Process_Mutex::dump (  void   )  const
 

Dump the state of an object.

Definition at line 44 of file RW_Process_Mutex.cpp.

References ACE_BEGIN_DUMP, ACE_DEBUG, ACE_END_DUMP, ACE_File_Lock::dump(), and LM_DEBUG. 

00045 {
00046 #if defined (ACE_HAS_DUMP)
00047 // ACE_TRACE ("ACE_RW_Process_Mutex::dump");
00048   ACE_DEBUG ((LM_DEBUG, ACE_BEGIN_DUMP, this));
00049   this->lock_.dump ();
00050   ACE_DEBUG ((LM_DEBUG, ACE_END_DUMP));
00051 #endif /* ACE_HAS_DUMP */
00052 }

ACE_INLINE const ACE_File_Lock & ACE_RW_Process_Mutex::lock (  void   )  const
 

Return the underlying lock.

Definition at line 71 of file RW_Process_Mutex.inl. 

00072 {
00073 // ACE_TRACE ("ACE_RW_Process_Mutex::lock");
00074   return this->lock_;
00075 }

ACE_INLINE int ACE_RW_Process_Mutex::release (  void   ) 
 

Release lock and unblock a thread at head of queue.

Definition at line 30 of file RW_Process_Mutex.inl.

References ACE_File_Lock::release(). 

00031 {
00032   return this->lock_.release ();
00033 }

ACE_BEGIN_VERSIONED_NAMESPACE_DECL ACE_INLINE int ACE_RW_Process_Mutex::remove (  void   ) 
 

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

Definition at line 9 of file RW_Process_Mutex.inl.

References ACE_File_Lock::remove(). 

00010 {
00011   return this->lock_.remove ();
00012 }

ACE_INLINE int ACE_RW_Process_Mutex::tryacquire (  void   ) 
 

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

Definition at line 23 of file RW_Process_Mutex.inl.

References ACE_File_Lock::tryacquire(). 

00024 {
00025   return this->lock_.tryacquire ();
00026 }

ACE_INLINE int ACE_RW_Process_Mutex::tryacquire_read (  void   ) 
 

Conditionally acquire a 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 51 of file RW_Process_Mutex.inl.

References ACE_File_Lock::tryacquire_read(). 

00052 {
00053   return this->lock_.tryacquire_read ();
00054 }

ACE_INLINE int ACE_RW_Process_Mutex::tryacquire_write (  void   ) 
 

Conditionally acquire a 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 58 of file RW_Process_Mutex.inl.

References ACE_File_Lock::tryacquire_write(). 

00059 {
00060   return this->lock_.tryacquire_write ();
00061 }

ACE_INLINE int ACE_RW_Process_Mutex::tryacquire_write_upgrade (  void   ) 
 

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

Definition at line 65 of file RW_Process_Mutex.inl.

References ACE_File_Lock::tryacquire_write_upgrade(). 

00066 {
00067   return this->lock_.tryacquire_write_upgrade ();
00068 }

ACE_BEGIN_VERSIONED_NAMESPACE_DECL const ACE_TCHAR * ACE_RW_Process_Mutex::unique_name (  void   )  [private]
 

Create and return the unique name.

Definition at line 24 of file RW_Process_Mutex.cpp.

References ACE_UNIQUE_NAME_LEN, and ACE::unique_name(). 

00025 {
00026   ACE::unique_name (this, this->name_, ACE_UNIQUE_NAME_LEN);
00027   return this->name_;
00028 }

Member Data Documentation

ACE_RW_Process_Mutex::ACE_ALLOC_HOOK_DECLARE
 

Declare the dynamic allocation hooks.

Definition at line 112 of file RW_Process_Mutex.h.

ACE_File_Lock ACE_RW_Process_Mutex::lock_ [private]
 

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

Definition at line 123 of file RW_Process_Mutex.h.

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.

Definition at line 117 of file RW_Process_Mutex.h.

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