"Dimitrie O. Paun" <[EMAIL PROTECTED]> writes:
> On November 27, 2003 01:38 am, Shachar Shemesh wrote:
>
>> While I will be happy to hear Dimi's rational for his, I
>> don't think there is much room for an actual "discussion",
>> as these things tend to turn into religious flame wars.
>
> There are some things that are _absolutely_ fundamental to
> the language, and one of them is that NULL is 0. The
> 'NULL' abstraction is paper thin, and it simply doesn't
> give you anything. Can you change the definition of NULL
> to, say, 1 on some architecture without breaking stuff
> left right and center? No.
Let me get into this (while waiting for my previous posts to
arrive to the list). I'd rather say that 0 is NULL. Of
course, NULL exists only in our minds, it's a #define, but
According to the language definition, a constant 0 in
a pointer context is converted into a null pointer at
compile time. <http://www.eskimo.com/~scs/C-faq/q5.2.html>
Also, we have to take care:
To generate a null pointer in a function call context,
an explicit cast may be required, to force the 0 to be
recognized as a pointer. For example, the Unix system
call execl takes a variable-length, null-pointer-
terminated list of character pointer arguments, and is
correctly called like this:
execl("/bin/sh", "sh", "-c", "date", (char *)0);
> So then what is its purpose, other than some sort of warm
> and fuzzy feeling of doing the 'right' thing? It just
> shows that we don't understand that in C values are either
> zero or non-zero, and that is the first stone at the
> foundation of the language, and you simply can not change
> that.
I can't agree with the above, see the surrsoundings of the
cited page. To cite more:
Summary:
Unadorned 0 okay: | Explicit cast required:
---------------------+----------------------------
initialization | function call,
| no prototype in scope
assignment |
| variable argument in
comparison | varargs function call
|
function call, |
prototype in scope, |
fixed argument |
Hmm, those winetests code samples seem to be missing in
action. I give them some more time, then repost them.
Feri.
