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