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 .