Another reason why - really /tmp

[BALDWIN]

> > /tmp is world writeable.  This means that anyone can unlink tmp files. 
> > In particular, my application wants to pass state data from a child
> > process to a parent prodcess via a tmp file that the child creates,
> > and there are windows of vulnerability in this scheme, due to the unlink
> > trouble.
> 
> Easy.  have your application make a subdirectory in /tmp, and then place
> a file within that subdir.  As long as your subdirectory is not world
> writeable, you can place tmp files there w/o having a window of vulnerability.

But anyone can still move the directory in /tmp, and put another one
in its place.  The problem is still there.
-- 
			 / These are \		Michael Baldwin
			|  only >my<  |		AT&T Bell Labs
			 \ opinions. /		{at&t}!whuxl!mike