CONTENTS

• NAME
• SYNOPSIS
• DESCRIPTION
• METHODS
• SEE ALSO
• AUTHORS
• COPYRIGHT

#NAME

IPC::SharedMem - SysV Shared Memory IPC object class

#SYNOPSIS

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;

#DESCRIPTION

A class providing an object based interface to SysV IPC shared memory.

#METHODS

#new ( KEY , SIZE , FLAGS )

Creates a new shared memory segment ofSIZE bytes size associated withKEY. A new segment is created if

• KEY is equal toIPC_PRIVATE

• KEY does not already have a shared memory segment associated with it, andFLAGS & IPC_CREAT is true.

On creation of a new shared memory segmentFLAGS is 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.

#id

Returns the shared memory identifier.

#read ( POS, SIZE )

ReadSIZE bytes from the shared memory segment atPOS. Returns the string read, orundef if there was an error. The return value becomes tainted. Seeshmread.

#write ( STRING, POS, SIZE )

WriteSIZE bytes to the shared memory segment atPOS. Returns true if successful, or false if there is an error. Seeshmwrite.

#remove

Remove the shared memory segment from the system or mark it as removed as long as any processes are still attached to it.

#is_removed

Returns true if the shared memory segment has been removed or marked for removal.

#stat

Returns an object of typeIPC::SharedMem::stat which is a sub-class ofClass::Struct. It provides the following fields. For a description of these fields see you system documentation.

uidgidcuidcgidmodesegszlpidcpidnattchatimedtimectime

#attach ( [FLAG] )

Permanently attach to the shared memory segment. When aIPC::SharedMem object is attached, it will usememread andmemwrite instead ofshmread andshmwrite for accessing the shared memory segment. Returns true if successful, or false on error. Seeshmat(2).

#detach

Detach from the shared memory segment that previously has been attached to. Returns true if successful, or false on error. Seeshmdt(2).

#addr

Returns the address of the shared memory that has been attached to in a format suitable for use withpack('P'). Returnsundef if the shared memory has not been attached.

#SEE ALSO

IPC::SysV,Class::Struct

#AUTHORS

Marcus Holland-Moritz <mhx@cpan.org>

#COPYRIGHT

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.

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