Xref: utzoo comp.unix.questions:6890 comp.unix.wizards:8301
Path: utzoo!mnetor!uunet!husc6!cmcl2!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: comp.unix.questions,comp.unix.wizards
Subject: Re: KSH portability
Message-ID: <7847@brl-smoke.ARPA>
Date: 6 May 88 19:00:36 GMT
References: <295@cmtl01.UUCP> <12142@tut.cis.ohio-state.edu> <631@vsi.UUCP> <4063@mtgzz.UUCP> <52159@sun.uucp> <5146@bloom-beacon.MIT.EDU>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 25

In article <5146@bloom-beacon.MIT.EDU> wolfgang@mgm.mit.edu (Wolfgang Rupprecht) writes:
>What *is* the "approved" method of finding all _iob's?

There isn't one.  This is an extremely implementation-dependent matter,
subject to change even between C releases for the same system.

The point of using <stdio.h> facilities to to encapsulate I/O streams
as an abstract data type.  If you really need to do something not
supported by the standard interface, you should either avoid using
<stdio.h> facilities or else work to get the standard interface
extended to provide whatever it is that you really need to do.  The
last example of this that I know of is an extension of fflush() so
that a NULL argument indicates a request to flush all open output
streams.  I got this adopted into the proposed ANSI C standard as
probably the last "invention" to make it into the standard (although
I proposed it over a year ago, it got overlooked until last meeting).
Buffer flushing before a fork() has been the only time I have needed
to cheat on the standard interface, and with this change to fflush()
EVENTUALLY that cheat won't be necessary.  Of course it will be a
while before I can rely on fflush() supporting this new feature, so
there will be an #if __STDC__ in the rare places where I need this
capability.

If your need to peek at the FILE implementation differs from this,
I'm curious to hear what it is.