NAME
ipcs — report status of interprocess communication facilities
SYNOPSIS
ipcs
[-mqs]
[-abcopt]
[-C
core]
[-N
namelist]
DESCRIPTION
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
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 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
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 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.
- 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
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
- /dev/kmem
Kernel virtual memory
- /etc/group
Group names
- /etc/passwd
User names
- /stand/vmunix
System namelist
STANDARDS CONFORMANCE
ipcs: SVID2, SVID3
Printable version
