ipcs(1) ipcs(1)
NAME [Toc] [Back]
ipcs - report status of interprocess communication facilities
SYNOPSIS [Toc] [Back]
ipcs [-mqs] [-abcopt] [-C core] [-N namelist]
DESCRIPTION [Toc] [Back]
ipcs displays certain information about active interprocess
communication facilities. With no options, ipcs displays information
in short format for the message queues, shared memory segments, and
semaphores that are currently active in the system.
Options [Toc] [Back]
The following options restrict the display to the corresponding
facilities.
(none) This is equivalent to -mqs.
-m Display information about active shared memory
segments.
-q Display information about active message queues.
-s Display information about active semaphores.
The following options add columns of data to the display. See "Column
Description" below.
(none) Display default columns: for all facilities: T,
ID, KEY, MODE, OWNER, GROUP.
-a Display all columns, as appropriate. This is
equivalent to -bcopt.
-b Display largest-allowable-size information: for
message queues: QBYTES; for shared memory
segments: SEGSZ; for semaphores: NSEMS.
-c Display creator's login name and group name: for
all facilities: CREATOR, CGROUP.
-o Display information on outstanding usage: for
message queues: CBYTES, QNUM; for shared memory
segments: NATTCH.
-p Display process number information: for message
queues: LSPID, LRPID; for shared memory segments:
CPID, LPID.
-t Display time information: for all facilities:
CTIME; for message queues: STIME, RTIME; for
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shared memory segments: ATIME, DTIME; for
semaphores: OTIME.
The following options redefine the sources of information.
-C core Use core in place of /dev/kmem. core can be a
core file or a directory created by savecrash or
savecore.
-N namelist Use file namelist or the namelist within core in
place of /stand/vmunix. It opens a crash dump for
reading. Please refer to cr_open(3) for more
details.
Column Descriptions [Toc] [Back]
The column headings and the meaning of the columns in an ipcs listing
are given below. The columns are printed from left to right in the
order shown below.
T Facility type:
m Shared memory segment
q Message queue
s Semaphore
ID The identifier for the facility entry.
KEY The key 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 The facility access modes and flags: The mode consists
of 11 characters that are interpreted as follows:
The first two characters can be:
R A process is waiting on a msgrcv().
S A process is waiting on a msgsnd().
D The associated shared memory segment has been
removed. It will disappear when the last
process attached to the segment detaches it.
C The associated shared memory segment is to be
cleared when the first attach is executed.
- The corresponding special flag is not set.
The next 9 characters are interpreted as three sets of
three characters each. The first set refers to the
owner's permissions, the next to permissions of others
in the group of the facility entry, and the last to all
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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.
r Read permission is granted.
w Write permission is granted.
a Alter permission is granted.
- The indicated permission is not granted.
OWNER The login name of the owner of the facility entry.
GROUP The group name of the group of the owner of the
facility entry.
CREATOR The login name of the creator of the facility entry.
CGROUP The group name of the group of the creator of the
facility entry.
CBYTES The number of bytes in messages currently outstanding
on the associated message queue.
QNUM The number of messages currently outstanding on the
associated message queue.
QBYTES The maximum number of bytes allowed in messages
outstanding on the associated message queue.
LSPID The process ID of the last process to send a message to
the associated message queue.
LRPID The process ID of the last process to receive a message
from the associated message queue.
STIME The time the last msgsnd() message was sent to the
associated message queue.
RTIME The time the last msgrcv() message was received from
the associated message queue.
CTIME The time when the associated facility entry was created
or changed.
NATTCH The number of processes attached to the associated
shared memory segment.
SEGSZ The size of the associated shared memory segment.
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ipcs(1) ipcs(1)
CPID The process ID of the creating process of the shared
memory segment.
LPID The process ID of the last process to attach or detach
the shared memory segment.
ATIME The time the last shmat() attach was completed to the
associated shared memory segment.
DTIME The time the last shmdt() detach was completed on the
associated shared memory segment.
NSEMS The number of semaphores in the set associated with the
semaphore entry.
OTIME The time the last semop() semaphore operation was
completed on the set associated with the semaphore
entry.
WARNINGS [Toc] [Back]
ipcs produces only an approximate indication of actual system status
because system processes are continually changing while ipcs is
acquiring the requested information.
Do not rely on the exact field widths and spacing of the output, as
these will vary depending on the system, the release of HP-UX, and the
data to be displayed.
FILES [Toc] [Back]
/dev/kmem Kernel virtual memory
/etc/group Group names
/etc/passwd User names
/stand/vmunix System namelist
SEE ALSO [Toc] [Back]
msgop(2), semop(2), shmop(2).
STANDARDS CONFORMANCE [Toc] [Back]
ipcs: SVID2, SVID3
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