Make a memory pool that is based on System V shared memory (shmget(2) etc.). This implementation allows memory to be shared between processes. If your platform doesn't support System V shared memory (e.g., Win32 and many RTOS platforms do not) then you should use ACE_MMAP_Memory_Pool instead of this class. In fact, you should probably use ACE_MMAP_Memory_Pool on platforms that do support System V shared memory since it provides more powerful features, such as persistent backing store and greatly scalability. More...

#include <Shared_Memory_Pool.h>

Inheritance diagram for ACE_Shared_Memory_Pool:

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Collaboration diagram for ACE_Shared_Memory_Pool:

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Classes
struct	SHM_TABLE
	Keeps track of all the segments being used. More...

Public Types
typedef ACE_Shared_Memory_Pool_Options	OPTIONS

Public Types inherited from ACE_Event_Handler
enum	{ LO_PRIORITY = 0, HI_PRIORITY = 10, NULL_MASK = 0, READ_MASK = (1 << 0), WRITE_MASK = (1 << 1), EXCEPT_MASK = (1 << 2), ACCEPT_MASK = (1 << 3), CONNECT_MASK = (1 << 4), TIMER_MASK = (1 << 5), QOS_MASK = (1 << 6), GROUP_QOS_MASK = (1 << 7), SIGNAL_MASK = (1 << 8), ALL_EVENTS_MASK, RWE_MASK, DONT_CALL = (1 << 9) }

enum	{ ACE_EVENT_HANDLER_NOT_RESUMED = -1, ACE_REACTOR_RESUMES_HANDLER = 0, ACE_APPLICATION_RESUMES_HANDLER }

typedef long	Reference_Count
	Reference count type.

Public Member Functions
	ACE_Shared_Memory_Pool (const ACE_TCHAR backing_store_name=0, const OPTIONS options=0)
	Initialize the pool.

virtual	~ACE_Shared_Memory_Pool (void)

virtual void *	init_acquire (size_t nbytes, size_t &rounded_bytes, int &first_time)
	Ask system for initial chunk of local memory.

virtual void *	acquire (size_t nbytes, size_t &rounded_bytes)

virtual int	release (int destroy=1)
	Instruct the memory pool to release all of its resources.

virtual int	sync (ssize_t len=-1, int flags=MS_SYNC)

virtual int	sync (void *addr, size_t len, int flags=MS_SYNC)
	Sync the memory region to the backing store starting at addr.

virtual int	protect (ssize_t len=-1, int prot=PROT_RDWR)

virtual int	protect (void *addr, size_t len, int prot=PROT_RDWR)

virtual void *	base_addr (void) const

virtual void	dump (void) const
	Dump the state of an object.

Public Member Functions inherited from ACE_Event_Handler
virtual	~ACE_Event_Handler (void)
	Destructor is virtual to enable proper cleanup.

virtual ACE_HANDLE	get_handle (void) const
	Get the I/O handle.

virtual void	set_handle (ACE_HANDLE)
	Set the I/O handle.

virtual int	priority (void) const

virtual void	priority (int priority)
	Set the priority of the Event_Handler.

virtual int	handle_input (ACE_HANDLE fd=ACE_INVALID_HANDLE)
	Called when input events occur (e.g., connection or data).

virtual int	handle_output (ACE_HANDLE fd=ACE_INVALID_HANDLE)

virtual int	handle_exception (ACE_HANDLE fd=ACE_INVALID_HANDLE)
	Called when an exceptional events occur (e.g., SIGURG).

virtual int	handle_timeout (const ACE_Time_Value &current_time, const void *act=0)

virtual int	handle_exit (ACE_Process *)
	Called when a process exits.

virtual int	handle_close (ACE_HANDLE handle, ACE_Reactor_Mask close_mask)

virtual int	resume_handler (void)

virtual int	handle_qos (ACE_HANDLE=ACE_INVALID_HANDLE)

virtual int	handle_group_qos (ACE_HANDLE=ACE_INVALID_HANDLE)

virtual void	reactor (ACE_Reactor *reactor)
	Set the event demultiplexors.

virtual ACE_Reactor *	reactor (void) const
	Get the event demultiplexors.

virtual ACE_Reactor_Timer_Interface *	reactor_timer_interface (void) const
	Get only the reactor's timer related interface.

virtual Reference_Count	add_reference (void)
	Increment reference count on the handler.

virtual Reference_Count	remove_reference (void)
	Decrement reference count on the handler.

Reference_Counting_Policy &	reference_counting_policy (void)
	Current Reference_Counting_Policy.

Public Attributes
	ACE_ALLOC_HOOK_DECLARE
	Declare the dynamic allocation hooks.

Protected Member Functions
virtual size_t	round_up (size_t nbytes)

virtual int	commit_backing_store_name (size_t rounded_bytes, ACE_OFF_T &offset)

virtual int	find_seg (const void *const searchPtr, ACE_OFF_T &offset, size_t &counter)
	Find the segment that contains the searchPtr.

virtual int	in_use (ACE_OFF_T &offset, size_t &counter)
	Determine how much memory is currently in use.

virtual int	handle_signal (int signum, siginfo_t , ucontext_t )

Protected Member Functions inherited from ACE_Event_Handler
	ACE_Event_Handler (ACE_Reactor *=0, int priority=ACE_Event_Handler::LO_PRIORITY)
	Force ACE_Event_Handler to be an abstract base class.

Protected Attributes
void *	base_addr_

size_t	file_perms_
	File permissions to use when creating/opening a segment.

size_t	max_segments_
	Number of shared memory segments in the <SHM_TABLE> table.

ACE_OFF_T	minimum_bytes_
	What the minimim bytes of the initial segment should be.

size_t	segment_size_
	Shared memory segment size.

key_t	base_shm_key_
	Base shared memory key for the segment.

ACE_Sig_Handler	signal_handler_
	Handles SIGSEGV.

Protected Attributes inherited from ACE_Event_Handler
Atomic_Reference_Count	reference_count_
	Reference count.

Additional Inherited Members
Static Public Member Functions inherited from ACE_Event_Handler
static ACE_THR_FUNC_RETURN	read_adapter (void *event_handler)

static int	register_stdin_handler (ACE_Event_Handler eh, ACE_Reactor reactor, ACE_Thread_Manager *thr_mgr, int flags=THR_DETACHED)

static int	remove_stdin_handler (ACE_Reactor reactor, ACE_Thread_Manager thr_mgr)
	Performs the inverse of the register_stdin_handler() method.

Protected Types inherited from ACE_Event_Handler
typedef ACE_Atomic_Op < ACE_SYNCH_MUTEX, Reference_Count >	Atomic_Reference_Count
	Typedef for implementation of reference counting.

Detailed Description

Make a memory pool that is based on System V shared memory (shmget(2) etc.). This implementation allows memory to be shared between processes. If your platform doesn't support System V shared memory (e.g., Win32 and many RTOS platforms do not) then you should use ACE_MMAP_Memory_Pool instead of this class. In fact, you should probably use ACE_MMAP_Memory_Pool on platforms that do support System V shared memory since it provides more powerful features, such as persistent backing store and greatly scalability.

Member Typedef Documentation

typedef ACE_Shared_Memory_Pool_Options ACE_Shared_Memory_Pool::OPTIONS

Constructor & Destructor Documentation

ACE_Shared_Memory_Pool::ACE_Shared_Memory_Pool	(	const ACE_TCHAR *	backing_store_name = `0`,
		const OPTIONS *	options = `0`
	)

Initialize the pool.

ACE_Shared_Memory_Pool::~ACE_Shared_Memory_Pool ( void )

virtual

Member Function Documentation

void * ACE_Shared_Memory_Pool::acquire	(	size_t	nbytes,
		size_t &	rounded_bytes
	)

virtual

Acquire at least nbytes from the memory pool. rounded_byes is the actual number of bytes allocated. Also acquires an internal semaphore that ensures proper serialization of Memory_Pool initialization across processes.

void * ACE_Shared_Memory_Pool::base_addr ( void ) const

virtual

Return the base address of this memory pool, 0 if base_addr never changes.

int ACE_Shared_Memory_Pool::commit_backing_store_name	(	size_t	rounded_bytes,
		ACE_OFF_T &	offset
	)

protectedvirtual

Commits a new shared memory segment if necessary after an <acquire> or a signal. offset is set to the new offset into the backing store.

void ACE_Shared_Memory_Pool::dump ( void ) const

virtual

Dump the state of an object.

int ACE_Shared_Memory_Pool::find_seg	(	const void *const	searchPtr,
		ACE_OFF_T &	offset,
		size_t &	counter
	)

protectedvirtual

Find the segment that contains the searchPtr.

int ACE_Shared_Memory_Pool::handle_signal	(	int	signum,
		siginfo_t *	siginfo,
		ucontext_t *
	)

protectedvirtual

Handle SIGSEGV and SIGBUS signals to remap shared memory properly.

Reimplemented from ACE_Event_Handler.

int ACE_Shared_Memory_Pool::in_use	(	ACE_OFF_T &	offset,
		size_t &	counter
	)

protectedvirtual

Determine how much memory is currently in use.

void * ACE_Shared_Memory_Pool::init_acquire	(	size_t	nbytes,
		size_t &	rounded_bytes,
		int &	first_time
	)

virtual

Ask system for initial chunk of local memory.

int ACE_Shared_Memory_Pool::protect	(	ssize_t	len = `-1`,
		int	prot = `PROT_RDWR`
	)

virtual

Change the protection of the pages of the mapped region to prot starting at this->base_addr_ up to len bytes. If len == -1 then change protection of all pages in the mapped region.

int ACE_Shared_Memory_Pool::protect	(	void *	addr,
		size_t	len,
		int	prot = `PROT_RDWR`
	)

virtual

Change the protection of the pages of the mapped region to prot starting at addr up to len bytes.

int ACE_Shared_Memory_Pool::release ( int destroy = 1 )

virtual

Instruct the memory pool to release all of its resources.

size_t ACE_Shared_Memory_Pool::round_up ( size_t nbytes )

protectedvirtual

Implement the algorithm for rounding up the request to an appropriate chunksize.

int ACE_Shared_Memory_Pool::sync	(	ssize_t	len = `-1`,
		int	flags = `MS_SYNC`
	)

virtual

Sync the memory region to the backing store starting at this->base_addr_.

int ACE_Shared_Memory_Pool::sync	(	void *	addr,
		size_t	len,
		int	flags = `MS_SYNC`
	)

virtual

Sync the memory region to the backing store starting at addr.

Member Data Documentation

ACE_Shared_Memory_Pool::ACE_ALLOC_HOOK_DECLARE

Declare the dynamic allocation hooks.

void* ACE_Shared_Memory_Pool::base_addr_

protected

Base address of the shared memory segment. If this has the value of 0 then the OS is free to select any address, otherwise this value is what the OS must try to use to map the shared memory segment.

key_t ACE_Shared_Memory_Pool::base_shm_key_

protected

Base shared memory key for the segment.

size_t ACE_Shared_Memory_Pool::file_perms_

protected

File permissions to use when creating/opening a segment.

size_t ACE_Shared_Memory_Pool::max_segments_

protected

Number of shared memory segments in the <SHM_TABLE> table.

ACE_OFF_T ACE_Shared_Memory_Pool::minimum_bytes_

protected

What the minimim bytes of the initial segment should be.

size_t ACE_Shared_Memory_Pool::segment_size_

protected

Shared memory segment size.

ACE_Sig_Handler ACE_Shared_Memory_Pool::signal_handler_

protected

Handles SIGSEGV.

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

Classes

Public Types

Public Member Functions

Public Attributes

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation