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From: Dan.Pop@cern.ch (Dan Pop)
Subject: Re: How big is an int? (was: Yet another stupid language war (was:
 ... the only languages you need!!))
Date: 1997/11/07
Message-ID: <danpop.878913108@news.cern.ch>#1/1
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References: <34557f2b.1934172@news.mindspring.com>
 <63qkp9$bqr$3@darla.visi.com> <63r2sv$rgm$1@helios.crest.nt.com>
 <878820761snz@genesis.demon.co.uk> <63t1j9$md8$1@helios.crest.nt.com>
Organization: CERN European Lab for Particle Physics
Newsgroups: 
 comp.lang.ada,comp.lang.c,comp.lang.c++,comp.lang.java.advocacy,comp.lang.c,comp.lang.c++
Date: 1997-11-07T00:00:00+00:00
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In <63t1j9$md8$1@helios.crest.nt.com> kaz@helios.crest.nt.com (Kaz Kylheku) writes:

>I forgot that you can check feof() and ferror(), which will resolve the
>ambiguity if EOF clashes.
>
>    unsigned char byte;
>
>    switch (ch = getc(stream)) {
>    /*...*/
>    case EOF:
>	if (feof(stream) || ferror(stream)) {
>	    /* handle */
>	} else {
>	    byte = EOF;		
>	}
>    /*...*/
>    }
>
>However, I doubt that very many programs actually do this. 

Few programs are intended to be portable to such platforms.  The main
reason being that all the implementations with sizeof(int) == 1 that I
know of are freestanding.  But someone who wants to write maximally
portable code had to do the error checking as shown above.

>Is a strictly conforming program required to deal with the possibility
>that EOF might not actually be an indicator of neither an error, nor
>the end of input?

Can a strictly conforming program perform *any* kind of I/O?  You cannot
predict the behaviour of the system from the text of the standard.  Part
of the definition of "strictly conforming program" says:

    It shall not produce output dependent on any unspecified, undefined, or
    implementation-defined behavior...

It is unspecified (or maybe implementation-defined) when an I/O operation
fails and if that failure affects the behaviour of your program...

Dan
--
Dan Pop
CERN, IT Division
Email: Dan.Pop@cern.ch 
Mail:  CERN - PPE, Bat. 31 1-014, CH-1211 Geneve 23, Switzerland