.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved 
.TH "<sys/ipc.h>" 0P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\" <sys/ipc.h> 
.SH NAME
sys/ipc.h \- XSI interprocess communication access structure
.SH SYNOPSIS
.LP
\fB#include <sys/ipc.h> \fP
.SH DESCRIPTION
.LP
The \fI<sys/ipc.h>\fP header is used by three mechanisms for XSI interprocess
communication (IPC): messages, semaphores,
and shared memory. All use a common structure type, \fBipc_perm\fP,
to pass information used in determining permission to perform
an IPC operation.
.LP
The \fBipc_perm\fP structure shall contain the following members:
.sp
.RS
.nf

\fBuid_t    uid   \fP Owner's user ID. \fB
gid_t    gid   \fP Owner's group ID. \fB
uid_t    cuid  \fP Creator's user ID. \fB
gid_t    cgid  \fP Creator's group ID. \fB
mode_t   mode  \fP Read/write permission. \fB
\fP
.fi
.RE
.LP
The \fBuid_t\fP, \fBgid_t\fP, \fBmode_t\fP, and \fBkey_t\fP types
shall be defined as described in \fI<sys/types.h>\fP .
.LP
Definitions shall be provided for the following constants:
.LP
Mode bits:
.TP 7
IPC_CREAT
Create entry if key does not exist.
.TP 7
IPC_EXCL
Fail if key exists.
.TP 7
IPC_NOWAIT
Error if request must wait.
.sp
.LP
Keys:
.TP 7
IPC_PRIVATE
Private key.
.sp
.LP
Control commands:
.TP 7
IPC_RMID
Remove identifier.
.TP 7
IPC_SET
Set options.
.TP 7
IPC_STAT
Get options.
.sp
.LP
The following shall be declared as a function and may also be defined
as a macro. A function prototype shall be provided.
.sp
.RS
.nf

\fBkey_t  ftok(const char *, int);
\fP
.fi
.RE
.LP
\fIThe following sections are informative.\fP
.SH APPLICATION USAGE
.LP
None.
.SH RATIONALE
.LP
None.
.SH FUTURE DIRECTIONS
.LP
None.
.SH SEE ALSO
.LP
\fI<sys/types.h>\fP, the System Interfaces volume of
IEEE\ Std\ 1003.1-2001, \fIftok\fP()
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .