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From: zog@nbisos.UUCP
Newsgroups: comp.lang.c
Subject: Re: NULL pointers as arguments
Message-ID: <148@nbisos.NBI.COM>
Date: Wed, 29-Apr-87 10:26:53 EDT
Article-I.D.: nbisos.148
Posted: Wed Apr 29 10:26:53 1987
Date-Received: Fri, 1-May-87 06:57:39 EDT
References: <1130@ius2.cs.cmu.edu>
Reply-To: zog@nbisos.UUCP (Chris Herzog)
Distribution: na
Organization: NBI  Boulder, CO
Lines: 33

In article <1130@ius2.cs.cmu.edu> edw@ius2.cs.cmu.edu (Eddie Wyatt) writes:
>
>   It seems to me that the problems of having foo(NULL) be correct on
>whatever machine you are working on could be taken care of by 
>having pointer arguements aways be type coerced into whatever the
>largest pointer type is on the machine (in cases presented to
>me that is char *).  This could be done as part of the language
>definition just as the float parameter are typed coerced into
>doubles.

This is NOT correct !

The fact that floats are passed as doubles is supported by the fact that
the compiler knows enough to coerce back when the called function picks
up the parameter.  It's still your responsibility to pass the correct types.

The main thrust here with pointers is that different types of pointers
can have COMPLETELY different representations.  Coercion to a common type
is not desireable.

All of these problems would go away if people would cast NULL to the
proper value.

"What about existing code which assumes .... ?"

Tough !  It's wrong !

We don't need to change the language definition to support junior programmers.
If you can't use a simple tool like lint, then step aside and let someone
who really cares do the task.  I'm so sick of all of the exceptions being
made to support and promote mediocrity !

Chris Herzog