Xref: utzoo comp.lang.c:31674 alt.lang.cfutures:47
Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!ncar!midway!mimsy!chris
From: chris@mimsy.umd.edu (Chris Torek)
Newsgroups: comp.lang.c,alt.lang.cfutures
Subject: Re: STDIO (Re: TRUE and FALSE)
Message-ID: <26431@mimsy.umd.edu>
Date: 7 Sep 90 21:43:28 GMT
References: <17632@haddock.ima.isc.com> <38Q5QG2@xds13.ferranti.com> <STEPHEN.90Sep7125034@estragon.uchicago.edu>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 35

In article <STEPHEN.90Sep7125034@estragon.uchicago.edu>
stephen@estragon.uchicago.edu (Stephen P Spackman) writes:
>Another thing that is needed is a function
>   FILE *pseudof
>     ( int (*producer)(void *handle, char *buf, size_t len)
>     , int (*consumer)(void *handle, char const *buf, size_t len)
>     , void *handle
>     , char const *mode
>     );
>
>that takes USER-DEFINED buffer readers and writers and makes a "FILE"
>object.

Gee, you mean like this one? :-)

	FILE *funopen(const void *_cookie,
		int (*readfn)(void *_cookie, char *_buf, int _n),
		int (*writefn)(void *_cookie, const char *_buf, int _n),
		fpos_t (*seekfn)(void *_cookie, fpos_t _off, int _whence),
		int (*closefn)(void *_cookie));

>That signature needs further thought - maybe it needs a flush/close
>function as well, e.g.; but it's not so far away.

No flush function is required, but seek and close functions are.

No `mode' is required either; this is implicit in the arguments.
(At least one of readfn and writefn must be non nil; if both are, the
function is a read-and-write.  All operations are `binary'; any `text'
conversion must be done in the read/write operations.)

This is running in the stdio on my 4.3BSD-reno-ish machine.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 405 2750)
Domain:	chris@cs.umd.edu	Path:	uunet!mimsy!chris