ACE_Shared_Memory_Pool Class Reference

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>

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List of all members.

Public Types

typedef ACE_Shared_Memory_Pool_Options OPTIONS

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

Classes

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

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,
off_t &  offset
[protected, virtual]
 

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,
off_t &  offset,
size_t &  counter
[protected, virtual]
 

Find the segment that contains the searchPtr.

int ACE_Shared_Memory_Pool::handle_signal int  signum,
siginfo_t ,
ucontext_t
[protected, virtual]
 

Handle SIGSEGV and SIGBUS signals to remap shared memory properly.

Reimplemented from ACE_Event_Handler.

int ACE_Shared_Memory_Pool::in_use off_t &  offset,
size_t &  counter
[protected, virtual]
 

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 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::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::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  )  [protected, virtual]
 

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

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.

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_.


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.

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:
Generated on Wed Nov 23 15:50:28 2005 for ACE by  doxygen 1.4.5