Re: 0 vs. NULL (RE: Worrisome warnings after recent patches)

Re: 0 vs. NULL (RE: Worrisome warnings after recent patches)

[Sven Wischnowsky]

Bruce Stephens wrote:

> Bernd Eggink <eggink@uni-hamburg.de> writes:
> 
> > Andrej Borsenkow wrote:
> 
> > > What is the point of using NULL to initialize null pointer. The only
> > > portable and official way is to use `0'(zero), that is garanteed to be
> > > converted to whatever representation null pointer has on a given system.
> > 
> > No, this applies to C++ only, not to C. In C you should use the NULL
> > macro or (void*)0.
> 
> There's an issue with arguments to functions which don't have
> prototypes, but apart from that, the literal 0 as a pointer should be
> fine in C.

Since the original message was a reaction to my patch: I know that `0' 
should be fine in C (at least with modern compilers) and personally I
prefer it. But using `NULL' is the convention used throughout the zsh
code, so...

Bye
 Sven


--
Sven Wischnowsky                         wischnow@informatik.hu-berlin.de

Re: 0 vs. NULL (RE: Worrisome warnings after recent patches)

[Bruce Stephens]

Bernd Eggink <eggink@uni-hamburg.de> writes:

> Andrej Borsenkow wrote:

> > What is the point of using NULL to initialize null pointer. The only
> > portable and official way is to use `0'(zero), that is garanteed to be
> > converted to whatever representation null pointer has on a given system.
> 
> No, this applies to C++ only, not to C. In C you should use the NULL
> macro or (void*)0.

There's an issue with arguments to functions which don't have
prototypes, but apart from that, the literal 0 as a pointer should be
fine in C.

Re: 0 vs. NULL (RE: Worrisome warnings after recent patches)

[Bernd Eggink]

Andrej Borsenkow wrote:
> 
> > +         Cline to, tn = NULL;
> 
> What is the point of using NULL to initialize null pointer. The only
> portable and official way is to use `0'(zero), that is garanteed to be
> converted to whatever representation null pointer has on a given system.

No, this applies to C++ only, not to C. In C you should use the NULL
macro or (void*)0. 

Bernd

--
Bernd Eggink
Regionales Rechenzentrum der Uni Hamburg
eggink@rrz.uni-hamburg.de
http://www.rrz.uni-hamburg.de/eggink/BEggink.html

0 vs. NULL (RE: Worrisome warnings after recent patches)

[Andrej Borsenkow]

> +	    Cline to, tn = NULL;

What is the point of using NULL to initialize null pointer. The only
portable and official way is to use `0'(zero), that is garanteed to be
converted to whatever representation null pointer has on a given system.

I mention it, because I just recently have seen quite a number of bug
reports, that rsulted exactly from using something like NULL for this.

Just a reminder ...

/andrej