sys_shm.h

<sys/shm.h>(P)						       <sys/shm.h>(P)



NAME
       sys/shm.h - XSI shared memory facility

SYNOPSIS
       #include <sys/shm.h>

DESCRIPTION
       The <sys/shm.h> header shall define the following symbolic constants:

       SHM_RDONLY
	      Attach read-only (else read-write).

       SHM_RND
	      Round attach address to SHMLBA.


       The <sys/shm.h> header shall define the following symbolic value:

       SHMLBA Segment low boundary address multiple.


       The following data types shall be defined through typedef:

       shmatt_t
	      Unsigned	integer	 used for the number of current attaches that
	      must be able to store values  at	least  as  large  as  a	 type
	      unsigned short.


       The shmid_ds structure shall contain the following members:


	      struct ipc_perm shm_perm	 Operation permission structure.
	      size_t	      shm_segsz	 Size of segment in bytes.
	      pid_t	      shm_lpid	 Process ID of last shared memory operation.
	      pid_t	      shm_cpid	 Process ID of creator.
	      shmatt_t	      shm_nattch Number of current attaches.
	      time_t	      shm_atime	 Time of last shmat
	       ().
	      time_t	      shm_dtime	 Time of last shmdt
	       ().
	      time_t	      shm_ctime	 Time of last change by shmctl
	       ().

       The  pid_t,  time_t,  key_t,  and  size_t  types	 shall	be defined as
       described in <sys/types.h> .

       The following shall be declared as functions and may also  be  defined
       as macros. Function prototypes shall be provided.


	      void *shmat(int, const void *, int);
	      int   shmctl(int, int, struct shmid_ds *);
	      int   shmdt(const void *);
	      int   shmget(key_t, size_t, int);

       In addition, all of the symbols from <sys/ipc.h> shall be defined when
       this header is included.

       The following sections are informative.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       <sys/ipc.h>  ,  <sys/types.h>  ,	 the  System  Interfaces  volume   of
       IEEE Std 1003.1-2001, shmat(), shmctl(), shmdt(), shmget()

COPYRIGHT
       Portions	 of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information  Technol-
       ogy  --	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 .



POSIX				     2003		       <sys/shm.h>(P)