ipcs(1) ipcs(1)
NAME
ipcs - report inter-process communication facilities status
SYNOPSIS
ipcs [options]
DESCRIPTION
ipcs prints information about active inter-process
communication facilities.
Note that information is displayed only for objects to which
the user has read access.
A user with the appropriate privileges is able to override the
read access restriction and display information on all
objects.
Without options, information is printed in short format for
message queues, shared memory, and semaphores that are
currently active in the system. Otherwise, the information
that is displayed is controlled by the following options:
-q Print information about active message queues.
-m Print information about active shared memory segments.
-s Print information about active semaphores.
If -q, -m, or -s are specified, information about only those
indicated is printed. If none of these three are specified,
information about all three is printed subject to these
options:
-b Print information on maximum 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 Print creator's login name and group name. See below.
-o Print 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.)
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ipcs(1) ipcs(1)
-p Print 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 Print time information. (Time of the last control
operation that changed the access permissions for all
facilities, time of last msgsnd and msgrcv operations on
message queues, time of last shmat and shmdt operations
on shared memory, and time of last semop operation on
semaphores.) See below.
-a Use all print options. (This is a shorthand notation
for -b, -c, -o, -p, -t.)
-C corefile
Use the file corefile in place of /dev/kmem.
-N namelist
Use the file namelist in place of /stand/unix.
-X Print information about XENIX interprocess
communication, in addition to the standard interprocess
communication status. The XENIX process information
describes a second set of semaphores and shared memory.
Note that the -p option does not print process number
information for XENIX shared memory, and the -t option does
not print time information about XENIX semaphores and shared
memory.
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 provided for each
facility; they do not determine which facilities are listed.
T (all) Type of facility:
q message queue
m shared memory segment
s semaphore
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ipcs(1) ipcs(1)
ID (all) The identifier for the facility entry.
KEY (all) 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 (all) The facility access modes and flags. The mode
consists of 11 characters that are interpreted
as follows:
The first character is:
S if a process is waiting on a msgsnd
operation.
- if the above is not true.
The second character is:
R if a process is waiting on a msgrcv
operation.
- if the above is not true.
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 if read permission is granted.
w if write permission is granted.
a if alter permission is granted.
- if the indicated permission is not
granted.
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ipcs(1) ipcs(1)
OWNER (all) The login name of the owner of the facility
entry.
GROUP (all) The group name of the owner of the facility
entry.
CREATOR (a,c) The login name of the creator of the facility
entry.
CGROUP (a,c) The group name of the creator of the facility
entry.
CBYTES (a,o) The number of bytes in messages currently
outstanding on the associated message queue.
QNUM (a,o) The number of messages currently outstanding
on the associated message queue.
QBYTES (a,b) The maximum number of bytes allowed in
messages outstanding on the associated message
queue.
LSPID (a,p) The process ID of the last process to send a
message to the associated queue.
LRPID (a,p) The process ID of the last process to receive
a message from the associated queue.
STIME (a,t) The time the last message was sent to the
associated queue.
RTIME (a,t) The time the last message was received from
the associated queue.
CTIME (a,t) The time the associated entry was created or
changed.
NATTCH (a,o) The number of processes attached to the
associated shared memory segment.
SEGSZ (a,b) The size of the associated shared memory
segment.
CPID (a,p) The process ID of the creator of the shared
memory entry.
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ipcs(1) ipcs(1)
LPID (a,p) The process ID of the last process to attach
or detach the shared memory segment.
ATIME (a,t) The time the last attach on the associated
shared memory segment was completed.
DTIME (a,t) The time the last detach on the associated
shared memory segment was completed.
NSEMS (a,b) The number of semaphores in the set associated
with the semaphore entry.
OTIME (a,t) The time the last semaphore operation on the
set associated with the semaphore entry was
completed.
FILES
/stand/unix system namelist
/dev/kmem memory
/etc/passwd user names
/etc/group group names
NOTES
If the user specifies the -N flag, the real and effective
UID/GID is set to the real UID/GID of the user invoking ipcs.
Things can change while ipcs is running; the information it
gives is guaranteed to be accurate only when it was retrieved.
REFERENCES
msgop(2), semop(2), shmop(2)
Copyright 1994 Novell, Inc. Page 5