Re: [c++] warn if NULL is passed through varargs

[Paul Koning <pkoning at equallogic dot com>]

>>>>> "Daniel" == Daniel Jacobowitz <drow@mvista.com> writes:

 Daniel> On Wed, Oct 09, 2002 at 01:24:34PM +1000, Fergus Henderson
 Daniel> wrote:
 >> On 08-Oct-2002, Andrew Pinski <pinskia@physics.uc.edu> wrote: > I
 >> think you need a test for this if you are going to > add it to
 >> show it works and will work for the future > so we do not have
 >> another feature that dies out like > `typedef X=0;'.  Also does
 >> this is a good idea for > the c front end too even though c
 >> requires NULL to > be a pointer type?
 >> 
 >> C does not require NULL to have a pointer type.  C requires NULL
 >> to be a null pointer constant, but that doesn't mean it has a
 >> pointer type; for example, `0' is a valid null pointer constant,
 >> and `0' has type `int', not a pointer type.  If you pass it
 >> through `...' then there is no guarantee that it will have the
 >> same representation as a null pointer.
 >> 
 >> So yes, this warning is a good idea for the C front end too.

 Daniel> You've got to be kidding.

 Daniel> - First of all, there's no real way to figure it out.  C++
 Daniel> has __null (spelling?), but C just has a NULL somewhere.
 Daniel> Defined usually as (void*) 0, at least for GCC.

I had the same reaction.  In C, NULL is just a #define, whose
definition varies.  I haven't actually done a census -- my own
favorite definition is simply 0 -- without any pointer casts that are
after all unnecessary.

      paul