07-03-2002
System V and POSIX IPCs
I am using SUN 0S 5.7.
My application has a dozen programs running in this machine, each instance of a program having 2 POSIX message queues for itself. Totally around 90 POSIX message queues.
Another small application uses a SYSTEM V shared memory and a message queue.
We face a problem here...whenever we boot up the small application, several instances of the bigger application(which uses POSIX queues) were shutting down. The small application doesnt do anything other than opening a System V shared memory, writes some data in it, and detaches. All IPC keys used in all programs are unique. No signals are handled or passed to other programs. There is absolutely no link between both the applications.
Will the System V and POSIX IPCs clash on any case, when run on the same machine?
Is there different "max queues limit" parameter in the same machine for POSIX and SystemV IPCs?
Deepa
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LEARN ABOUT FREEBSD
ipcrm
IPCRM(1) BSD General Commands Manual IPCRM(1)
NAME
ipcrm -- remove the specified message queues, semaphore sets, and shared segments
SYNOPSIS
ipcrm [-W] [-v] [-q msqid] [-m shmid] [-s semid] [-Q msgkey] [-M shmkey] [-S semkey] ...
DESCRIPTION
The ipcrm utility removes the specified message queues, semaphores and shared memory segments. These System V IPC objects can be specified
by their creation ID or any associated key.
The following options are generic:
-v If specified once with -W or with -1 for an object, it will show all removed objects. If specified twice with -W or with -1 for an
objects, it will show all removed objects and all failed removals.
-W Try to wipe all specified message queues, semaphores and shared memory segments.
-y Use the kvm(3) interface instead of the sysctl(3) interface to extract the required information. If ipcrm is to operate on the run-
ning system, using kvm(3) will require read privileges to /dev/kmem.
The following options are used to specify which IPC objects will be removed. Any number and combination of these options can be used:
-q msqid
Remove the message queue associated with the ID msqid from the system.
-m shmid
Mark the shared memory segment associated with ID shmid for removal. This marked segment will be destroyed after the last detach.
-s semid
Remove the semaphore set associated with ID semid from the system.
-Q msgkey
Remove the message queue associated with key msgkey from the system.
-M shmkey
Mark the shared memory segment associated with key shmkey for removal. This marked segment will be destroyed after the last detach.
-S semkey
Remove the semaphore set associated with key semkey from the system.
The identifiers and keys associated with these System V IPC objects can be determined by using ipcs(1). If the identifier or the key is -1,
it will remove all these objects.
SEE ALSO
ipcs(1)
HISTORY
The wiping of all System V IPC objects was first implemented in FreeBSD 6.4 and 7.1.
AUTHORS
The original author was Adam Glass. The wiping of all System V IPC objects was thought up by Callum Gibson and extended and implemented by
Edwin Groothuis.
BSD
December 12, 2007 BSD