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)