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Newsgroups: comp.os.msdos.djgpp
Subject: Re: scanf: strange behavior?
References: <20040902144152 DOT GH6858 AT webhome DOT cz>
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Date: Thu, 02 Sep 2004 19:08:36 GMT
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Egon Eckert wrote:
> 
> compiling and running this code:
> 
> #include <stdio.h>
> 
> int main(int, const char**)
> {
>   char c[2];
>   printf("%d\n", sscanf("A", "%c%c", c, c + 1));
>   return 0;
> }
> 
> gives:
> 
> 1 in GNU libc (on Linux)
> 1 in Borland C++ 3.1 (on DOS)
> -1 in djgpp
> 
> It's conformant with the docs: "If input ends, or if there is any
> input failure before the first item is converted and assigned, `EOF'
> is returned.", so it's not to be called a 'bug', but...
> 
> Do you think it's a standard violation, or just a "difference",
> ie. behavior not specified by POSIX, ANSI or other (involved)
> authority?

I think DJGPP is correct in returning EOF, because the string ends
before the scan is complete.  The only authority is the C
standard.  I would consider it a library bug on Borland and your
particular Linux installation of libc.  This is better suited to
comp.lang.c.

At least all three signalled a failure.

-- 
Some useful references:
  <http://www.ungerhu.com/jxh/clc.welcome.txt>
  <http://www.eskimo.com/~scs/C-faq/top.html>
  <http://benpfaff.org/writings/clc/off-topic.html>
  <http://anubis.dkuug.dk/jtc1/sc22/wg14/www/docs/n869/> (C99)
  <http://www.dinkumware.com/refxc.html> C-library