Re: [PATCH] Futex Asynchronous Interface

From: Linus Torvalds (torvalds@transmeta.com)
Date: Sat Jun 08 2002 - 17:28:26 EST


On Fri, 7 Jun 2002, Peter Wächtler wrote:
>
> What about /proc/futex then?

Why?

Tell me _one_ advantage from having the thing exposed as a filename?

The whole point with "everything is a file" is not that you have some
random filename (indeed, sockets and pipes show that "file" and "filename"
have nothing to do with each other), but the fact that you can use common
tools to operate on different things.

But there's absolutely no point in opening /dev/futex from a shell script
or similar, because you don't get anything from it. You still have to bind
the fd to it's real object.

In short, the name "/dev/futex" (or "/proc/futex") is _meaningless_.
There's no point to it. It has no life outside the FUTEX system call, and
the only thing that you can do by exposing it as a name is to cause
problems for people who don't want to mount /proc, or who do not happen to
have that device node in their /dev.

> Give it an entry in the namespace, why not with sockets (unix and ip) also?

Perhaps because you cannot enumerate sockets and pipes? They don't _have_
names before they are created. Same as futexes, btw.

                Linus

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