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ipcs(1)								      ipcs(1)



NAME

  ipcs - Reports Interprocess Communication (IPC) facility status

SYNOPSIS

  ipcs [-a  | -bcopt] [-mqs] [-C corefile] [-N namelist]

  The ipcs command writes to the standard output information about active
  Interprocess Communication (IPC) facilities.

STANDARDS

  Interfaces documented	on this	reference page conform to industry standards
  as follows:

  ipcs:	XCU5.0

  Refer	to the standards(5) reference page for more information	about indus-
  try standards	and associated tags.

OPTIONS

  -a  Same as specifying the -b, -c, -o, -p, and -t options.

  -b  Writes the maximum number	of bytes in message queues, the	size of	seg-
      ments for	shared memory, and the number of semaphores in each semaphore
      set.

  -c  Writes the username and group name of the	user that made the facility.

  -C corefile
      Writes report based on contents of file corefile instead of /dev/kmem.

  -m  Writes information about active shared memory segments.

  -N namelist
      Writes report based on contents of file namelist instead of /vmunix.

  -o  Writes the following usage information:

	+  Number of messages on queue

	+  Total number	of bytes in message queues

	+  Number of processes attached	to shared memory segments

  -p  Writes the following:

	+  Process number of the last process to receive a message on message
	   queues

	+  Process number of the creating process

	+  Process number of last process to attach or detach on shared
	   memory segments

  -q  Writes information about active message queues.

  -s  Writes information about active semaphore	set.

  -t  Writes the following:

	+  Time	of the last control operation that changed the access permis-
	   sions for all facilities

	+  Time	of the last msgsnd() and last msgrcv() on message queues

	+  Time	of the last shmat() and	last shmdt() on	shared memory

	+  Time	of the last semop() on semaphore sets

DESCRIPTION

  If you do not	specify	any options, ipcs writes information in	a short	form
  about	currently active message queues, shared	memory segments, semaphores,
  remote queues, and local queue headers.

  Column Headings


  The column headings and the meaning of the columns in	an ipcs	listing	fol-
  low.	The letters in parentheses indicate the	flags that cause the
  corresponding	heading	to appear.  The	word all means that the	heading
  always appears.  The flags only determine what information is	provided for
  each facility; they do not determine which facilities	are listed.

  T (all)
      Type of facility:

      q	  Message queue

      m	  Shared memory	segment

      s	  Semaphore

  ID (all)
      The identifier for the facility entry.

  KEY (all)
      The key used as a	parameter to the msgget(), semget() or shemget() sys-
      tem calls	to make	the facility entry.

      Note that	the key	of a shared memory segment is changed to IPC_PRIVATE
      when the segment is removed. This	change remains	in effect until	all
      processes	attached to the	segment	detach it.

  MODE (all)
      The facility access modes	and flags. The mode consists of	11 characters
      that are interpreted as follows:

      The first	two characters can be:

      L	  [Tru64 UNIX]	If the associated shared memory	segment	was locked.

      R	  If a process is waiting on a msgrcv()	system call.

      S	  If a process is waiting on a msgsnd()	system call.

      D	  If the associated shared memory segment was removed. It disappears
	  when the last	process	attached to the	segment	detaches it.

      -	  If the corresponding special flag is not set.

      The next nine characters are interpreted as three	sets of	three bits
      each.  The first set refers to the owner's permissions, the next to
      permissions of others in the user	group of the facility entry, and the
      last to all others.  Within each set, the	first character	indicates
      permission to read, the second character indicates permission to write
      or alter the facility entry, and the last	character is currently
      unused.

      The permissions are indicated as follows:

      r	  Read permission is granted.

      w	  Write	permission is granted.

      a	  Alter	permission is granted.

      -	  The indicated	permission is not granted.

  OWNER	(all)
      The username of the owner	of the facility	entry.

  GROUP	(all)
      The name of the group that owns the facility entry.

  CREATOR (a,c)
      The username of the creator of the facility entry.

  CGROUP (a,c)
      The group	name of	the group of the creator of the	facility entry.

      Note that	for the	OWNER, GROUP, CREATOR, and CGROUP, the user and	group
      IDs display instead of the usernames.

  CBYTES (a,o)
      The number of bytes in messages currently	outstanding on the associated
      message queue.

  QNUM (a,o)
      The number of messages currently outstanding on the associated message
      queue.

  QBYTES (a,b)
      The maximum number of bytes allowed in messages outstanding on the
      associated message queue.

  LSPID	(a,p)
      The ID of	the last process that sent a message to	the associated queue.

  LRPID	(a,p)
      The ID of	the last process that received a message from the associated
      queue.

  STIME	(a,t)
      The time when the	last message was sent to the associated	queue.

  RTIME	(a,t)
      The time when the	last message was received from the associated queue.

  CTIME	(a,t)
      The time when the	associated entry was created or	changed.

  NATTCH (a,o)
      The number of processes attached to the associated shared	memory seg-
      ment.

  SEGSZ	(a,b)
      The size of the associated shared	memory segment.

  CPID (a,p)
      The process ID of	the creator of the shared memory entry.

  LPID (a,p)
      The process ID of	the last process to attach or detach the shared
      memory segment.

  ATIME	(a,t)
      The time when the	last attach was	completed to the associated shared
      memory segment.

  DTIME	(a,t)
      The time when the	last detach was	completed on the associated shared
      memory segment.

  NSEMS	(a,b)
      The number of semaphores in the set associated with the semaphore
      entry.

  OTIME	(a,t)
      The time when the	last semaphore operation was completed on the set
      associated with the semaphore entry.

EXAMPLES

  Sample output	from entering ipcs without options follows.

	Message	Queues:
	T      ID	 KEY	MODE	     OWNER    GROUP
	q	4 0x41002ab4 --rw-------      root   system

	Shared Memory:
	T      ID	 KEY	MODE	     OWNER    GROUP
	m	0 0x3253bc5c --rw-rw-rw-      root   system
	m     129	   0 DLrw-------      root   daemon

	Semaphores:
	T      ID	 KEY	MODE	     OWNER    GROUP
	s	0 0x41002ab4 --ra-------      root   system

  Output is formatted differently if the environment variable CMD_ENV is set
  to the string	svr4.  For example:

	IPC status from	/dev/kmem as of	Thu Mar	26 11:31:03 1998
	T      ID	 KEY	MODE	     OWNER    GROUP
	Message	Queues:
	q	4 0x41002ab4 --rw-------      root   system
	Shared Memory:
	m	0 0x3253bc5c --rw-rw-rw-      root   system
	m     129	   0 DLrw-------      root   daemon
	Semaphores:
	s	0 0x41002ab4 --ra-------      root   system








FILES

  /etc/passwd
      Contains user information.

  /etc/group
      Contains group information.

SEE ALSO

  Commands:  ipcrm(1)

  Functions:  msgrcv(2), msgsnd(2), semop(2), shmat(2),	shmdt(2)