sys_ipc.h(7POSIX) POSIX Programmer's Manual sys_ipc.h(7POSIX)
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.
sys/ipc.h — XSI interprocess communication access structure
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 operation.
The <sys/ipc.h> header shall define the ipc_perm structure, which shall include the fol‐
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
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 func‐
tion prototype shall be provided.
key_t ftok(const char *, int);
The following sections are informative.
The System Interfaces volume of POSIX.1‐2008, ftok()
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 discrep‐
ancy 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 https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 sys_ipc.h(7POSIX)