IPCS(1) DOMAIN/IX Reference Manual (SYS5) IPCS(1)
NAME
ipcs - report interprocess communication facilities status
USAGE
ipcs [ options ]
DESCRIPTION
Ipcs prints certain information about active interprocess
communication facilities, depending on specified options.
By default, information is printed in short format for mes-
sage queues, shared memory, and semaphores currently active
in the system. Unless you specify a -q, -m, or -s option,
ipcs prints information about all three types of facilities.
OPTIONS
-q Print information about active message queues.
-m Print information about active shared memory seg-
ments.
-s Print information about active semaphores.
-b Print information about the largest allowable size
for the facility. This includes the 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 the meaning of columns in a listing.
-c Print creator's log-in name and group name. See
below.
-o Print information on outstanding usage. This
includes the number of messages on queue and total
number of bytes in messages on queue for message
queues, and the number of processes attached to
shared memory segments.
-p Print process number information. This includes
the process ID of the following: last process to
send a message, last process to receive a message
on message queues, creating process, and last pro-
cess to attach or detach on shared memory seg-
ments. See below.
-t Print time of the last control operation that
changed the access permissions for all facilities,
last msgsnd and last msgrcv on message queues,
last shmat and last shmdt on shared memory, and
last semop (2) on semaphores. See below.
-a Print all information individually available
Printed 6/10/85 IPCS-1
IPCS(1) DOMAIN/IX Reference Manual (SYS5) IPCS(1)
through the -b, -c, -o, -p, and -t options.
IPCS-2 Printed 6/10/85
IPCS(1) DOMAIN/IX Reference Manual (SYS5) IPCS(1)
OUTPUT INTERPRETATION
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; all means that the heading always appears. Note
that these options only determine what information is pro-
vided for each facility; they do not determine which facili-
ties are listed.
T (all) Type of facility:
q message queue
m shared memory segment
s semaphore
ID (all) Identifier for the facility entry.
KEY (all) Key is used as an argument to msgget,
semget, or shmget 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) Facility access modes and flags. The mode
consists of 11 characters in all.
The first two characters may be one each
from the following sets, or one of the char-
acters followed by a dash (-) (to signify
that the corresponding special flag was not
set), or a double dash (- -).
The first set describes information about
message queues:
R process is waiting on a msgrcv
S process is waiting on a msgsnd
The second set describes information about
shared memory segments:
D associated shared memory segment
has been removed (i.e., will disap-
pear when the last process attached
to the segment detaches it)
C associated shared memory segment is
cleared when the first attach is
executed
The next nine characters describe various
types of permissions. They 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 shows permission to read, and the
Printed 6/10/85 IPCS-3
IPCS(1) DOMAIN/IX Reference Manual (SYS5) IPCS(1)
second character shows permission to write
or alter the facility entry. The last char-
acter is currently unused.
Permissions are indicated as follows:
r read permission is granted
w write permission is granted
a alter permission is granted
- indicated permission is not
granted.
OWNER (all) Log-in name of the user who owns the facil-
ity entry.
GROUP (all) Group name of the group in which the owner
of the facility entry belongs.
CREATOR(a,c) Log-in name of the user who created the
facility entry.
CGROUP (a,c) Group name of the group in which the creator
of the facility entry belongs.
CBYTES (a,o) Number of bytes in messages currently out-
standing on the associated message queue.
QNUM (a,o) Number of messages currently outstanding on
the associated message queue.
QBYTES (a,b) Maximum number of bytes allowed in messages
outstanding on the associated message queue.
LSPID (a,p) Process ID of the last process to send a
message to the associated queue.
LRPID (a,p) Process ID of the last process to receive a
message from the associated queue.
STIME (a,t) Time the last message was sent to the asso-
ciated queue.
RTIME (a,t) Time the last message was received from the
associated queue.
CTIME (a,t) Time when the associated entry was created
or changed.
NATTCH (a,o) Number of processes attached to the associ-
ated shared memory segment.
SEGSZ (a,b) Size of the associated shared memory seg-
ment.
CPID (a,p) Process ID of the creator of the shared
memory entry.
LPID (a,p) Process ID of the last process to attach or
detach the shared memory segment.
ATIME (a,t) Time the last attach was completed to the
associated shared memory segment.
DTIME (a,t) Time the last detach was completed on the
associated shared memory segment.
NSEMS (a,b) Number of semaphores in the set associated
with the semaphore entry.
OTIME (a,t) Time the last semaphore operation was com-
pleted on the set associated with the sema-
phore entry.
IPCS-4 Printed 6/10/85
IPCS(1) DOMAIN/IX Reference Manual (SYS5) IPCS(1)
CAUTIONS
The status of interprocess communication facilities can
change so rapidly that the information produced by ipcs is
only correct for the very moment that you query the system.
FILES
/etc/passwd usernames
/etc/group groupnames
RELATED INFORMATION
msgop (2), semop (2), shmop (2).
Printed 6/10/85 IPCS-5