posix
Class SharedMem

java.lang.Object
  posix.IPC
      posix.SharedMem

public class SharedMem
extends IPC

A Posix shared memory segment. Shared physical memory is not supported, since this requires superuser privilege and is very hardware dependent.

Nested Class Summary

static class

SharedMem.shmid_ds

Nested classes/interfaces inherited from class posix.IPC

IPC.Perm

Field Summary

static long

SHMLBA The modulus for attaching shared memory by logical address.

Fields inherited from class posix.IPC

egid, euid, id, IPC_ALLOC, IPC_CI, IPC_CREAT, IPC_EXCL, IPC_NOCLEAR, IPC_NOWAIT, IPC_PHYS, IPC_PRIVATE, owner, pid

Constructor Summary

SharedMem(int key, int flag)
Attach an existing shared memory segment.

SharedMem(int key, int size, int flag)
Attach or create a shared memory segment.

SharedMem(java.lang.String path, int type)

Method Summary

CPtr	attach()
void	dispose()
IPC.Perm	getPerm() Return the permissions for this IPC data structure.
SharedMem.shmid_ds	getStatus()
void	remove() Remove this IPC data structure from the system.

Methods inherited from class posix.IPC

finalize, ftok, getId, isPidValid

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

SHMLBA

public static final long SHMLBA

The modulus for attaching shared memory by logical address. This is system dependent and therefore computed by the class initializer. While attaching shared memory to a specific address is somewhat system dependent, it is easily handled by configuration or property settings.

Constructor Detail

SharedMem

public SharedMem(int key,
                 int flag)
          throws IPCException

Attach an existing shared memory segment.

Throws:

IPCException

SharedMem

public SharedMem(int key,
                 int size,
                 int flag)
          throws IPCException

Attach or create a shared memory segment.

Parameters:

key - IPC key or IPC_PRIVATE

size - size of shared memory

flag - options

Throws:

IPCException

SharedMem

public SharedMem(java.lang.String path,
                 int type)
          throws IPCException

Throws:

IPCException

Method Detail

getStatus

public SharedMem.shmid_ds getStatus()
                             throws IPCException

Throws:

IPCException

getPerm

public IPC.Perm getPerm()
                 throws IPCException

Description copied from class: IPC

Return the permissions for this IPC data structure.

Specified by:

getPerm in class IPC

Throws:

IPCException

attach

public CPtr attach()
            throws IPCException

Throws:

IPCException

remove

public void remove()

Description copied from class: IPC

Remove this IPC data structure from the system.

Specified by:

remove in class IPC

dispose

public void dispose()

Overrides:

dispose in class IPC