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 ipc_perm structure shall contain 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 uid_t, gid_t, mode_t, and key_t types shall be defined as described in <sys/types.h> .

       Definitions shall be provided for the following 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 IEEE Std 1003.1-2001, ftok()

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 .