Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!att!att!ima!dirtydog!karl
From: karl@ima.isc.com (Karl Heuer)
Newsgroups: comp.lang.c
Subject: Re: problem with fread/fwrite
Keywords: fread, fwrite, file pointers
Message-ID: <1990Nov14.014352.14586@dirtydog.ima.isc.com>
Date: 14 Nov 90 01:43:52 GMT
References: <402@bally.Bally.COM> <14384@smoke.brl.mil> <13992@ulysses.att.com> <2677@cirrusl.UUCP> <3337@bruce.cs.monash.OZ.AU>
Sender: news@dirtydog.ima.isc.com (NEWS ADMIN)
Reply-To: karl@ima.isc.com (Karl Heuer)
Organization: Interactive Systems
Lines: 18

In article <3337@bruce.cs.monash.OZ.AU> cechew@bruce.cs.monash.OZ.AU (Earl Chew) writes:
>The main obstacle to switching between reads and writes is:
>1. the behaviour of early implementations of stdio
>2. subsequent casting of (1) in concrete by ANSI-C

X3J11 did not freeze this behavior.  They declined to correct it (and quite
properly so, if there was no existing practice), but the fix is a valid
conforming extension.  It would even be possible for some other standard, like
POSIX, to require it.

>I am unsure whether ANSI-C prohibits stdio implementations from automatic
>switching, but it clear that if such a feature were to be implemented, its
>use would make the application non-conforming.

True (as does, say, the use of "isatty()").  But if the vendors add it now, it
might be required behavior by the time C-2001 is done.

Karl W. Z. Heuer (karl@ima.isc.com or uunet!ima!karl), The Walking Lint