ipcs
IPCS(1) General Commands Manual IPCS(1)
NAME
ipcs – report System V interprocess communication facilities status
SYNOPSIS
ipcs [-abcMmopQqSsTt]
DESCRIPTION
The ipcs utility provides information on System V interprocess
communication (IPC) facilities on the system.
The options are as follows:
-a Show the maximum amount of information possible when displaying
active semaphores, message queues, and shared memory segments.
(This is shorthand for specifying the -b, -c, -o, -p, and -t
options.)
-b Show the maximum allowed sizes for active semaphores, message
queues, and shared memory segments. The “maximum allowed size” is
the maximum number of bytes in a message on a message queue, the
size of a shared memory segment, or the number of semaphores in a
set of semaphores.
-c Show the creator's name and group for active semaphores, message
queues, and shared memory segments.
-M Display system information about shared memory.
-m Display information about active shared memory segments.
-o Show outstanding usage for active message queues, and shared memory
segments. The “outstanding usage” is the number of messages in a
message queue, or the number of processes attached to a shared
memory segment.
-p Show the process ID information for active semaphores, message
queues, and shared memory segments. The “process ID information”
is the last process to send a message to or receive a message from
a message queue, the process that created a semaphore, or the last
process to attach or detach a shared memory segment.
-Q Display system information about messages queues.
-q Display information about active message queues.
-S Display system information about semaphores.
-s Display information about active semaphores.
-T Display system information about shared memory, message queues and
semaphores.
-t Show access times for active semaphores, message queues, and shared
memory segments. The access times is the time of the last control
operation on an IPC object, the last send or receive of a message,
the last attach or detach of a shared memory segment, or the last
operation on a semaphore.
If none of the -M, -m, -Q, -q, -S, or -s options are specified, information
about all active IPC facilities is listed.
RESTRICTIONS
System data structures may change while ipcs is running; the output of ipcs
is not guaranteed to be consistent.
BUGS
This manual page is woefully incomplete, because it does not at all attempt
to explain the information printed by ipcs.
SEE ALSO
ipcrm(1)
AUTHORS
Thorsten Lockert ⟨tholo@sigmasoft.com⟩
macOS 12.1 June 18, 1994 macOS 12.1