ipcs — report
System V interprocess communication facilities status
ipcs |
[-abcMmopQqSsTt] [-u
user] |
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.
-u- Display information about IPC mechanisms owned by
user. User specification can be in the form of a
numeric UID or a login name.
If none of the -M,
-m, -Q,
-q, -S, or
-s options are specified, information about all
active IPC facilities is listed.
System data structures may change while
ipcs is running; the output of
ipcs is not guaranteed to be consistent.
This manual page is woefully incomplete, because it does not at
all attempt to explain the information printed by
ipcs.