MQUEUEFS(5)

💖 MQUEUEFS(5) — the POSIX message queue file system, explained by your fav unix bestie 💅

okay so real talk, this is the mqueuefs(5) page from the File Formats Manual, and honestly? it's giving "underrated icon" energy. let's get into it ✨

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🌸 NAME 🌸

mqueuefs — the POSIX message queue file system, and yes bestie she's literally that girl 🎀

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✨ SYNOPSIS ✨

so there's two ways to get her into your life, depending on the vibe you're going for:

To link into kernel:

options P1003_1B_MQUEUE

To load as a kernel loadable module:

kldload mqueuefs

pick your fighter, both are valid, no cap 💅

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🦋 DESCRIPTION 🦋

okay so here's the tea: the mqueuefs module lets the FreeBSD kernel support POSIX message queue. not just support it — the module contains system calls to manipulate POSIX message queues. iconic behavior honestly 🔥

and it doesn't stop there. it also contains a file system to implement a view for all message queues of the system. the way that just... helps users keep track of their message queues?? and makes it more easily usable without having to invent additional tools?? obsessed. genuinely so thoughtful of it 🫶

The most common usage is as follows:

mount -t mqueuefs null /mnt/mqueue

where /mnt/mqueue is a mount point. that's it. that's the move ✨

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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. cute, right? 🎀

⚠️ but listen — using /mnt/mqueue as a permanent mount point is not advised. its intention has always been to be a temporary mount point. that's just her nature, okay? see hier(7) for more information on FreeBSD directory layout 💖

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Some common tools can be used on the file system, e.g.: cat(1), chmod(1), chown(8), ls(1), rm(1), etc. the whole squad showing up for her, we love to see it 🌈

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. lowkey flexible of her 💅

now, manually creating a file, for example, touch /mnt/mqueue/myqueue, will create a message queue named myqueue in the kernel, and default message queue attributes will be applied to the queue. 🍓

🙈 BUT. 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. main character move: do it the right way, bestie.

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to see the queue's attributes, just read the file:

cat /mnt/mqueue/myqueue

literally that simple. no extra steps. periodt 👑

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🔥 SEE ALSO 🔥

• mq_open(2)
• nmount(2)
• unmount(2)
• mount(8)
• umount(8)

go read them, iykyk 💜

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👑 AUTHORS 👑

this manual page was written by David Xu <davidxu@FreeBSD.org>. thank you David, you ate 💅✨

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and that's the whole page! this version came from Debian, dated November 30, 2005 — a true vintage icon, still slaying to this day 🎀💖🦋