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$FreeBSD$
.Dd November 30, 2005 .Dt MQUEUEFS 5 .Os .Sh NAME .Nm mqueuefs .Nd POSIX message queue file system .Sh SYNOPSIS To link into kernel:
p .Cd "options P1003_1B_MQUEUE"
p To load as a kernel loadable module:
p .Dl "kldload mqueuefs" .Sh DESCRIPTION The .Nm module will permit the .Fx kernel to support .Tn POSIX message queue. The module contains system calls to manipulate .Tn POSIX message queues. It also contains a file system to implement a view for all message queues of the system. This helps users to keep track of their message queues and make it more easily usable without having to invent additional tools.
p The most common usage is as follows:
p .Dl "mount -t mqueuefs null /mnt/mqueue"
p where
a /mnt/mqueue is a mount point.
p It is possible to define an entry in
a /etc/fstab that looks similar to: d -literal null /mnt/mqueue mqueuefs rw 0 0 .Ed
p This will mount .Nm at the
a /mnt/mqueue mount point during system boot. Using
a /mnt/mqueue as a permanent mount point is not advised as its intention has always been to be a temporary mount point. See .Xr hier 7 for more information on .Fx directory layout.
p Some common tools can be used on the file system, e.g.: .Xr cat 1 , .Xr chmod 1 , .Xr chown 8 , .Xr ls 1 , .Xr 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 module or compile it into the kernel. Manually creating a file, for example, .Dq Li "touch /mnt/mqueue/myqueue" , will create a message queue named
a 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 .Xr mq_open 2 system call to create a queue as it allows the user to specify different attributes.
p To see the queue's attributes, just read the file:
p .Dl "cat /mnt/mqueue/myqueue" .Sh SEE ALSO .Xr mq_open 2 , .Xr nmount 2 , .Xr unmount 2 , .Xr mount 8 , .Xr umount 8 .Sh AUTHORS This manual page was written by .An "David Xu" Aq davidxu@FreeBSD.org .