# IPC::SysV - phpMan

## NAME
    [IPC::SysV] - System V IPC constants and system calls

## SYNOPSIS
      use [IPC::SysV] qw(IPC_STAT IPC_PRIVATE);

## DESCRIPTION
    "[IPC::SysV]" defines and conditionally exports all the constants defined
    in your system include files which are needed by the SysV IPC calls.
    Common ones include

      IPC_CREAT IPC_EXCL IPC_NOWAIT IPC_PRIVATE IPC_RMID IPC_SET IPC_STAT
      GETVAL SETVAL GETPID GETNCNT GETZCNT GETALL SETALL
      SEM_A SEM_R SEM_UNDO
      SHM_RDONLY SHM_RND SHMLBA

    and auxiliary ones

      S_IRUSR S_IWUSR S_IRWXU
      S_IRGRP S_IWGRP S_IRWXG
      S_IROTH S_IWOTH S_IRWXO

    but your system might have more.

    ftok( PATH )
    ftok( PATH, ID )
        Return a key based on PATH and ID, which can be used as a key for
        "msgget", "semget" and "shmget". See [ftok(3)].

        If ID is omitted, it defaults to 1. If a single character is given
        for ID, the numeric value of that character is used.

    shmat( ID, ADDR, FLAG )
        Attach the shared memory segment identified by ID to the address
        space of the calling process. See [shmat(2)].

        ADDR should be "undef" unless you really know what you're doing.

    shmdt( ADDR )
        Detach the shared memory segment located at the address specified by
        ADDR from the address space of the calling process. See [shmdt(2)].

    memread( ADDR, VAR, POS, SIZE )
        Reads SIZE bytes from a memory segment at ADDR starting at position
        POS. VAR must be a variable that will hold the data read. Returns
        true if successful, or false if there is an error. memread() taints
        the variable.

    memwrite( ADDR, STRING, POS, SIZE )
        Writes SIZE bytes from STRING to a memory segment at ADDR starting
        at position POS. If STRING is too long, only SIZE bytes are used; if
        STRING is too short, nulls are written to fill out SIZE bytes.
        Returns true if successful, or false if there is an error.

## SEE ALSO
    [IPC::Msg], [IPC::Semaphore], [IPC::SharedMem], [ftok(3)], [shmat(2)], [shmdt(2)]

## AUTHORS
    Graham Barr <<gbarr@pobox.com>>, Jarkko Hietaniemi <<jhi@iki.fi>>, 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.