4 Aug
2008
4 Aug
'08
2:14 p.m.
On Monday 04 August 2008, Sean Conner wrote:
It was thus said that the Great Tony Duell once
stated:
The C Standard say the token "0" (in a pointer context) is to be
translated to a null address in the target architecture, and in most
implementations, that address is indeed 0, but it doesn't have to be.
C also does not require that the value of a pointer be the actual
address stored by the pointer. You could have said that the actual
address is the value of the pointer minus 2^31 (or 2^15, 2^19 or
whatever).
In any case, C does not require that the physical/logical address "0" is
equivalent to NULL, only that the value of a pointer is NULL if its
value is "0".
Pat
--
Purdue University Research Computing --- http://www.rcac.purdue.edu/
The Computer Refuge --- http://computer-refuge.org
will offend someone. I think Intel putting them
at the bottom
sounds like a fine design, at least in the '70s. 'C' and it's
desire to have address 0 be NULL was not around on the micros,
and putting it at the
I wasn't aware that this was a requirement of C, or any other
language.