On Fri, Nov 27, 2009 at 2:24 PM, Nicolas Cellier <
nicolas.cellier.aka.nice at gmail.com> wrote:

> 2009/11/27 Colin Putney <cputney at wiresong.ca>:
> >
> > On 27-Nov-09, at 8:03 AM, David T. Lewis wrote:
> >
> >> I implemented IOHandle for this, see http://wiki.squeak.org/squeak/996.
> >> I have not maintained it since about 2003, but the idea is
> >> straightforward.
> >
> > Yes. I looked into IOHandle when implementing Filesystem, but decided to
> go
> > with a new (simpler, but limited) implementation that would let me
> explore
> > the requirements for the stream architecture I had in mind.
> >
> >> My purpose at that time was to :
> >>
> >>  * Separate the representation of external IO channels from the
> >> represention
> >>   of streams and communication protocols.
> >>  * Provide a uniform representation of IO channels similar to the unix
> >> notion
> >>   of treating everything as a 'file'.
> >>  * Simplify future refactoring of Socket and FileStream.
> >>  * Provide a place for handling asynchronous IO events. Refer to the aio
> >>   handling in the unix VM. Files, Sockets, and AsyncFiles could (should)
> >> use
> >>   a common IO event handling mechanism (aio event signaling a Smalltalk
> >> Semaphore).
> >
> > Indeed. Filesystem comes at this from the other direction, but I think we
> > want to end up in the same place. For now I've done TSTTCPW, which is use
> > the primitives from the FilePlugin. But eventually I want to improve the
> > plumbing. You've done some important work here - perhaps Filesystem can
> use
> > AioPlugin at some point.
> >
> > Colin
> >
> >
>
> I wonder why level 3 stdio was used (FILE * fopen, fclose ...) rather
> than level 2 (int fid, open, close, ...) in file plugin... Better
> portability ?
>

level 2 isn't really a level, its a section of the unix manual pages.
 Section 2 is the system calls (which really define what unix is).  Section
3 is libraries.  So only the stdio library in section 3 is portable across C
implementations.  So yes, you're right, the use of the C library's stdio
facilities was chosen for portability.

>
> Nicolas
>
>
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