PROLOG

       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.

NAME

       sys/ipc.h — XSI interprocess communication access structure

SYNOPSIS

       #include <sys/ipc.h>

DESCRIPTION

       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 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.

       Mode bits:

       IPC_CREAT   Create entry if key does not exist.

       IPC_EXCL    Fail if key exists.

       IPC_NOWAIT  Error if request must wait.

       Keys:

       IPC_PRIVATE Private key.

       Control commands:

       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.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       <sys_types.h>

       The System Interfaces volume of POSIX.1‐2017, ftok()

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard
       for Information  Technology  --  Portable  Operating  System  Interface  (POSIX),  The  Open  Group  Base
       Specifications  Issue  7, 2018 Edition, Copyright (C) 2018 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 .

       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 .