IPCS(1) User Commands IPCS(1)

NAME

ipcs - report inter-process communication facilities status

SYNOPSIS

ipcs [-aAbciJmopqstZ] [-D mtype] [-z zone]

DESCRIPTION

The ipcs utility prints information about active inter-process
communication facilities. The information that is displayed is controlled
by the options supplied. Without options, information is printed in short
format for message queues, shared memory, and semaphores that are
currently active in the system.

OPTIONS

The following options are supported:

-m
Prints information about active shared memory segments.


-q
Prints information about active message queues.


-s
Prints information about active semaphores.


If -m, -q, or -s are specified, information about only those indicated is
printed. If none of these three is specified, information about all three
is printed subject to these options:

-a
Uses all XCU5 print options. (This is a shorthand notation
for -b, -c, -o, -p, and -t.)


-A
Uses all print options. (This is a shorthand notation for -b,
-c, -i, -J, -o, -p, and -t.)


-b
Prints information on biggest allowable size: maximum number
of bytes in messages on queue for message queues, size of
segments for shared memory, and number of semaphores in each
set for semaphores. See below for meaning of columns in a
listing.


-c
Prints creator's login name and group name. See below.


-D mtype
Displays, in hexadecimal and ASCII, the contents of all
messages of type mtype found on any message queue that the
user invoking ipcs has permission to read. If mtype is 0, all
messages are displayed. If mtype is negative, all messages
with type less than or equal to the absolute value of mtype
are displayed. (See msgrcv(2) and msgsnap(2)).


-i
Prints number of ISM attaches to shared memory segments.


-J
Prints the creator's project.


-o
Prints information on outstanding usage: number of messages
on queue and total number of bytes in messages on queue for
message queues and number of processes attached to shared
memory segments.


-p
Prints process number information: process ID of last process
to send a message, process ID of last process to receive a
message on message queues, process ID of creating process,
and process ID of last process to attach or detach on shared
memory segments. See below.


-t
Prints time information: time of the last control operation
that changed the access permissions for all facilities, time
of last msgsnd(2) and last msgrcv(2) on message queues, time
of last shmat(2) and last shmdt(2) on shared memory (see
shmop(2)), time of last semop(2) on semaphores. See below.


-z zone
Prints information about facilities associated with the
specified zone (see zones(7)). The zone can be specified as
either a name or a numeric id. The default is to display
information about the zone in which the command is executing.
Notice that this option is only useful when executing in the
global zone.


-Z
When executing in the global zone, prints information about
all zones. Otherwise, prints information about the zone in
which the command is executing. The output includes the zone
associated with each facility.


The column headings and the meaning of the columns in an ipcs listing are
given below. The letters in parentheses indicate the options that cause
the corresponding heading to appear and "all" means that the heading
always appears. Note: These options only determine what information is
provided for each facility; they do not determine which facilities are
listed.

T (all)
Type of the facility:

q
message queue


m
shared memory segment


s
semaphore


ID (all)
The identifier for the facility entry.


KEY (all)
The key used as an argument to msgget(2), semget(2),
or shmget(2) to create the facility entry. (Note: The
key of a shared memory segment is changed to
IPC_PRIVATE when the segment has been removed 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 are:

R
A process is waiting on a msgrcv(2).


S
A process is waiting on a msgsnd(2).


-
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 login name of the owner of the facility entry.


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


CREATOR (a,A,c)
The login name of the creator of the facility entry.


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


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


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


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


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


LRPID (a,A,p)
The process ID of the last process to receive a
message from the associated queue.


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


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


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


ISMATTCH (a,i)
The number of ISM attaches to the associated shared
memory segments.


NATTCH (a,A,o)
The number of processes attached to the associated
shared memory segment.


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


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


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


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


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


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


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


PROJECT (J,A)
The project name of the creator of the facility entry.


ZONE (Z)
The zone with which the facility is associated.

ENVIRONMENT VARIABLES

See environ(7) for descriptions of the following environment variables
that affect the execution of ipcs: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES,
and NLSPATH.

TZ
Determine the timezone for the time strings written by ipcs.

FILES

/etc/group
group names


/etc/passwd
user names

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------+
|Interface Stability | Committed |
+--------------------+-------------------+
|Standard | See standards(7). |
+--------------------+-------------------+

SEE ALSO

ipcrm(1), msgget(2), msgids(2), msgrcv(2), msgsnap(2), msgsnd(2),
semget(2), semids(2), semop(2), shmctl(2), shmget(2), shmids(2),
shmop(2), attributes(7), environ(7), standards(7), zones(7)

NOTES

Things can change while ipcs is running. The information it gives is
guaranteed to be accurate only when it was retrieved.

January 17, 2008 IPCS(1)