MQUEUEFS(5) BSD File Formats Manual MQUEUEFS(5)NAME
mqueuefs — POSIX message queue file system
SYNOPSIS
To link into kernel:
options P1003_1B_MQUEUE
To load as a kernel loadable module:
kldload mqueuefs
DESCRIPTION
The mqueuefs module will permit the FreeBSD kernel to support POSIX mes‐
sage queue. The module contains system calls to manipulate POSIX message
queues. It also contains a file system to implement a view for all mes‐
sage queues of the system. This helps users to keep track of their mes‐
sage queues and make it more easily usable without having to invent addi‐
tional tools.
The most common usage is as follows:
mount -t mqueuefs null /mnt/mqueue
where /mnt/mqueue is a mount point.
It is possible to define an entry in /etc/fstab that looks similar to:
null /mnt/mqueue mqueuefs rw 0 0
This will mount mqueuefs at the /mnt/mqueue mount point during system
boot. Using /mnt/mqueue as a permanent mount point is not advised as its
intention has always been to be a temporary mount point. See hier(7) for
more information on FreeBSD directory layout.
Some common tools can be used on the file system, e.g.: cat(1), chmod(1),
chown(8), ls(1), rm(1), etc. To use only the message queue system calls,
it is not necessary for user to mount the file system, just load the mod‐
ule or compile it into the kernel. Manually creating a file, for exam‐
ple, “touch /mnt/mqueue/myqueue”, will create a message queue named
myqueue in the kernel, default message queue attributes will be applied
to the queue. It is not advised to use this method to create a queue; it
is better to use the mq_open(2) system call to create a queue as it
allows the user to specify different attributes.
To see the queue's attributes, just read the file:
cat /mnt/mqueue/myqueue
SEE ALSOmq_open(2), nmount(2), unmount(2), mount(8), umount(8)AUTHORS
This manual page was written by David Xu ⟨davidxu@FreeBSD.org⟩.
BSD November 30, 2005 BSD