This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
The <sys/ipc.h> header is used by three mechanisms for XSI
interprocess communication (IPC): messages, semaphores, and shared
memory. All use a common structure type, ipc_perm, to pass
information used in determining permission to perform an IPC
The <sys/ipc.h> header shall define the ipc_perm structure, which
shall include the following members:
uid_t uid Owner's user ID.
gid_t gid Owner's group ID.
uid_t cuid Creator's user ID.
gid_t cgid Creator's group ID.
mode_t mode Read/write permission.
The <sys/ipc.h> header shall define the uid_t, gid_t, mode_t, and
key_t types as described in <sys/types.h>.
The <sys/ipc.h> header shall define the following symbolic constants.
IPC_CREAT Create entry if key does not exist.
IPC_EXCL Fail if key exists.
IPC_NOWAIT Error if request must wait.
IPC_PRIVATE Private key.
IPC_RMID Remove identifier.
IPC_SET Set options.
IPC_STAT Get options.
The following shall be declared as a function and may also be defined
as a macro. A function prototype shall be provided.
key_t ftok(const char *, int);The following sections are informative.
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) 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.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
IEEE/The Open Group 2013 sys_ipc.h(0P)