Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!crdgw1!uunet!mcsun!ukc!acorn!RMokady
From: RMokady@acorn.co.uk (Ran "The horrible little oik" Mokady)
Newsgroups: comp.sys.acorn
Subject: Re: Pseudo Filing Systems via *set
Message-ID: <6830@acorn.co.uk>
Date: 3 May 91 13:26:54 GMT
References: <6815@acorn.co.uk>
Sender: rmokady@acorn.co.uk
Distribution: comp
Organization: Acorn Computers Ltd, Cambridge, England
Lines: 45

In article <6815@acorn.co.uk> osmith@acorn.co.uk (Owen Smith) writes:

>Try *set foo$dir adfs::4.$.fred
>    *setmacro foo$path <foo$dir>.,adfs::4.$.fred2.
>
>Now, when you try to read a file eg. *dump foo:wombat, all of the directories
>on the path variable foo$path will be searched. If you do something
>that needs a single directory eg. *dir foo:, *cat foo:, *create foo:fred
>then the single directory in foo$dir will be used.
>
>This is not secret information. Various of the !Boot and !Run files in the
>RiscOS TcpIp suite set path and dir variables. So does C release 3 - look
>at CLib$Dir, CLib$Path, Risc_OSLib$Dir and Risc_OSLib$Path.
>
>Doing *show * from time to time and perusing the output can be quite
>interesting.
>
>Owen.
>
>The views expressed are my own and are not necessarily those of Acorn.
  
I think Owen got things a bit wrong.

   It is not possible to do any operation which requires a write on anything
which contains a pseudo filing system reference - RISC OS simply doesn't
know which directory to use.

   Things like the Risc OS TCP/IP suite set path variables in order to
enable you to add other directories in the search list, when they are
READING the files.

   In short, path variables can only be used to add directories to a search
path when reading files, even operations such as *cat path: do not work.



             Ran.



-----
"We're children, Needing other children
 And yet letting our grown up pride
 Hide all the need inside
 Acting more like children than children"