ipcs(1) User Commands ipcs(1)
ipcs - report inter-process communication facilities status
ipcs [-aAbciJmopqstZ] [-D mtype] [-z zone]
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.
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
-a Uses all XCU5 print options. (This is a shorthand notation for -b, -c, -o, -p,
-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 mes-
sages 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 col-
umns 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 pro-
cesses attached to shared memory segments.
-p Prints process number information: process ID of last process to send a mes-
sage, 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(5)). 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 exe-
cuting. Notice that this option is only useful when executing in the global
-Z When executing in the global zone, prints information about all zones. Other-
wise, 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
T (all) Type of the facility:
q message queue
m shared memory segment
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 per-
missions of others in the user-group of the facility entry; and the
last to all others. Within each set, the first character indicates per-
mission 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
QNUM (a,A,o) The number of messages currently outstanding on the associated message
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
LRPID (a,A,p) The process ID of the last process to receive a message from the asso-
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 seg-
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 mem-
ATIME (a,A,t) The time the last attach was completed to the associated shared memory
DTIME (a,A,t) The time the last detach was completed on the associated shared memory
NSEMS (a,A,b) The number of semaphores in the set associated with the semaphore
OTIME (a,A,t) The time the last semaphore operation was completed on the set associ-
ated 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.
See environ(5) 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.
/etc/group group names
/etc/passwd user names
See attributes(5) for descriptions of the following attributes:
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|Availability |SUNWipc |
|Interface Stability |Committed |
|Standard |See standards(5). |
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(5), environ(5), stan-
Things can change while ipcs is running. The information it gives is guaranteed to be
accurate only when it was retrieved.
SunOS 5.11 17 Jan 2008 ipcs(1)