Path: utzoo!mnetor!uunet!sdrc!scjones
From: scjones@sdrc.UUCP (Larry Jones)
Newsgroups: comp.lang.c
Subject: Re: Machine specific predefined names
Message-ID: <229@sdrc.UUCP>
Date: 22 Feb 88 23:36:27 GMT
References: <1988Feb17.115402.12739@light.uucp> <17033@watmath.waterloo.edu>
Organization: Structural Dynamics Research Corp., Cincinnati
Lines: 25

In article <17033@watmath.waterloo.edu>, rbutterworth@watmath.waterloo.edu (Ray Butterworth) writes:
> But consider a different related problem:
> 
>     #include <stdlib.h>
>     #include <stdio.h>
>     int putchar(int n) { abort(n); }
>     main() { perror("xx"); }
> 
> Now if perror() needs putchar() to write the message, will it use
> my version of putchar or an internal version, say _putchar()?
[stuff omitted for brevity]
> I didn't see anything in the standard to indicate that either of
> these behaviours is right or wrong.

The draft clearly indicates in section 4.1.2 that every external identifier
declared in a standard header is reserved whether the header is included or
not and that redefining a reserved external identifier results in undefined
behaviour.  Thus, either behaviour is acceptable and your program is not
strictly portable.

----
Larry Jones                         UUCP: uunet!sdrc!scjones
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