13 Nov 2020 17:02:18 UTC
- Distribution: IPC-SysV
- Module version: 2.09
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IPC::SharedMem - SysV Shared Memory IPC object class
use IPC::SysV qw(IPC_PRIVATE S_IRUSR S_IWUSR); use IPC::SharedMem; $shm = IPC::SharedMem->new(IPC_PRIVATE, 8, S_IRWXU); $shm->write(pack("S", 4711), 2, 2); $data = $shm->read(0, 2); $ds = $shm->stat; $shm->remove;
A class providing an object based interface to SysV IPC shared memory.
- new ( KEY , SIZE , FLAGS )
Creates a new shared memory segment of
SIZEbytes size associated with
KEY. A new segment is created if
KEYis equal to
KEYdoes not already have a shared memory segment associated with it, and
FLAGS & IPC_CREATis true.
On creation of a new shared memory segment
FLAGSis used to set the permissions. Be careful not to set any flags that the Sys V IPC implementation does not allow: in some systems setting execute bits makes the operations fail.
Returns the shared memory identifier.
- read ( POS, SIZE )
SIZEbytes from the shared memory segment at
POS. Returns the string read, or
undefif there was an error. The return value becomes tainted. See shmread.
- write ( STRING, POS, SIZE )
SIZEbytes to the shared memory segment at
POS. Returns true if successful, or false if there is an error. See shmwrite.
Remove the shared memory segment from the system or mark it as removed as long as any processes are still attached to it.
Returns true if the shared memory segment has been removed or marked for removal.
Returns an object of type
IPC::SharedMem::statwhich is a sub-class of
Class::Struct. It provides the following fields. For a description of these fields see you system documentation.
uid gid cuid cgid mode segsz lpid cpid nattch atime dtime ctime
- attach ( [FLAG] )
Permanently attach to the shared memory segment. When a
IPC::SharedMemobject is attached, it will use memread and memwrite instead of shmread and shmwrite for accessing the shared memory segment. Returns true if successful, or false on error. See shmat(2).
Detach from the shared memory segment that previously has been attached to. Returns true if successful, or false on error. See shmdt(2).
Returns the address of the shared memory that has been attached to in a format suitable for use with
undefif the shared memory has not been attached.
Marcus Holland-Moritz <firstname.lastname@example.org>
Version 2.x, Copyright (C) 2007-2013, Marcus Holland-Moritz.
Version 1.x, Copyright (c) 1997, Graham Barr.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.