Re: [Fwd: Re: GCC headers and DJGPP port (OT)]

[Mo McKinlay <mmckinlay at gnu dot org>]

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# I personally hate using NULL anywhere in C/C++ code.

Hmm. Personally, I feel the opposite. When reading code, it's useful to see
NULL - especially if it's only used with pointer types - because it makes it
obvious to the reader that the lvalue is a pointer and not an integer.
 
# Perhaps, one use of (void *)0 would be to restrict its comparison or
# assignment to int, char, long, ... types. I don't see this advantage as
# significant or important. To try to stop programmers from writing "int
# i=NULL;" is in the direction of trying to stop car-owners from putting
# sand
# in their gas-tanks.

I don't think it's aim is to specifically *stop* users doing this. As with
cars, if a car owner really wants to put sand in her gas-tank, he will.

However, it *does* improve source code legibility. And in the same way as:

 foo.c:7: warning: passing arg 1 of 'bar' makes pointer from integer without
    cast.

It makes it clear that you're dealing with something that wants a pointer,
and not a numeric type. And when you're hacking someone else's code, being
able to see this stuff quickly and easily is very useful indeed.

Consider:

int bar(int, char *, char *, int, char *, size_t);

And somewhere in the sources:

 r=bar(0, 0, 0, 0, 0, 0);

Without referring to the definition of 'bar', could you say which is the
second char * argument?

Whereas:

 r=bar(0, NULL, NULL, 0, NULL, 0);

Makes it obvious straight away.

My 2c.

- -- 
Mo McKinlay             Chief Software Architect          inter/open Labs
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GnuPG Key: pub  1024D/76A275F9 2000-07-22 Mo McKinlay <mmckinlay@gnu.org>





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