perldoc > IPC::SysV

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📖 NAME

IPC::SysV - System V IPC constants and system calls

🚀 Quick Reference

Use Case	Command	Description
Get IPC key	ftok(PATH, ID)	Return a key based on PATH and ID for use with msgget, semget, shmget
Attach shared memory	shmat(ID, ADDR, FLAG)	Attach shared memory segment to address space
Detach shared memory	shmdt(ADDR)	Detach shared memory segment
Read from shared memory	memread(ADDR, VAR, POS, SIZE)	Read SIZE bytes from memory segment at ADDR
Write to shared memory	memwrite(ADDR, STRING, POS, SIZE)	Write SIZE bytes to memory segment at ADDR
Import IPC constants	use IPC::SysV qw(IPC_STAT IPC_PRIVATE);	Import constants for SysV IPC 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 AT pobox.com>, Jarkko Hietaniemi <jhi AT iki.fi>, Marcus Holland-Moritz <mhx AT 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.

📖 NAME 🚀 Quick Reference 📝 SYNOPSIS 📖 DESCRIPTION 🔗 SEE ALSO 👤 AUTHORS © COPYRIGHT