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From: ast@cs.vu.nl (Andy Tanenbaum)
Newsgroups: comp.os.minix
Subject: Re: Compiling 1.5.0 commands
Message-ID: <5451@star.cs.vu.nl>
Date: 18 Feb 90 21:12:47 GMT
References: <1552@crash.cts.com>
Sender: news@cs.vu.nl
Organization: Fac. Wiskunde & Informatica, VU, Amsterdam
Lines: 41

In article <1552@crash.cts.com> cwr@pnet01.cts.com (Will Rose) writes:
>In a recent article, nfs@notecnirp.UUCP (Norbert Schlenker) writes:
> 
>>An extraordinary number of commands generate warnings when compiled,
>>most of which are caused by the definition of NULL as ((void *)0).

I looked at the cdiffs Norbert posted.  About half were real and I 
incorporated them where they did not conflict with other fixes.  The
other half were due to POSIX_SOURCE, which should be defined in the
Makefile.  In any event, it is now.

Also, there is one nasty thingie in 1.5.3.  In all the ANSI headers except
<stdio.h>, NULL is defined as ((void *) 0).  In <stdio.h> it is defined as

#ifdef NULL
#undef NULL
#endif
#define NULL 0

This means that a file using <stdio.h> gets NULL as a 0, and a file using
the other gets it as the void pointer.  In case both kinds of headers are
used, I carefully put #include <stdio.h> last, so you get a true 0.  This
wreaks havoc with the Atari, so Frans Meulenbroeks and I have put in casts
everywhere where it matters.

Please DO NOT TELL ME THIS IS AN UGLY HACK.  I know very well it is an ugly
hack.  The problem is that I have gone over to POSIX/ANSI headers for
everything except <stdio.h>, and the old <stdio.h> uses a 0.  When our ANSI
C compiler is finished, I will go over to its <stdio.h> header, and I didn't
want to change it twice, once now (e.g., to Earl's) and later to our ANSI C
header.  Despite the ugliness of this hack, it is essentially temporary, which
is why I am not sweating it too much.  Since headers are always defined with
<stdio.h> last, something ANSI clearly allows, all programs are legal now
and will remain legal with the ANSI compiler.  The only effect this ugliness
has now is to require a few casts that might otherwise not be required
with an ANSI C compiler and full prototypes.  It's not that awful and it will
go away eventually.

The appearance of 1.5.3 is imminent.

Andy Tanenbaum (ast@cs.vu.nl)