basic pointer code

[pauldepstein@att.net]

I don't quite understand some code that looks like this

int zeronumber = 0;
SomeMember.Some Function(&zeron umber);

I'm almost sure that SomeFunction is a function defined on pointer-to-
int, and is here being applied to the null pointer. But, if I'm
right, it would seem that SomeFunction would be applied to
(zeronumber) rather than (&zeronumber) . &zeronumber would seem to
mean "the address of a null pointer" which doesn't make sense. I'm
basically confused by the ampersand in front of zeronumber.

Thank you,

Paul Epstein

[terminator]

Re: basic pointer code

On Oct 28, 11:11 am, pauldepst...@at t.net wrote:

I don't quite understand some code that looks like this
>
int zeronumber = 0;
SomeMember.Some Function(&zeron umber);
>
I'm almost sure that SomeFunction is a function defined on pointer-to-
int, and is here being applied to the null pointer. But, if I'm
right, it would seem that SomeFunction would be applied to
(zeronumber) rather than (&zeronumber) . &zeronumber would seem to
mean "the address of a null pointer" which doesn't make sense. I'm
basically confused by the ampersand in front of zeronumber.
>

the address of an object is distinct from its value.'zeronumb er' is
not a pointer ,it is an integer initialized to zero.'&zeronumb er' is a
pointer addressing the location of an integer which is named as
'zeronumber' ,since it is the address of a named object it cn not be
null.Here is the definition of a pointer initailized to null:

int * intptr=0;

cheers,
FM.

[pauldepstein@att.net]

Re: basic pointer code

On Oct 28, 4:49 pm, terminator <farid.mehr...@ gmail.comwrote:

On Oct 28, 11:11 am, pauldepst...@at t.net wrote:
>

I don't quite understand some code that looks like this

>

int zeronumber = 0;
SomeMember.Some Function(&zeron umber);

>

I'm almost sure that SomeFunction is a function defined on pointer-to-
int, and is here being applied to the null pointer. But, if I'm
right, it would seem that SomeFunction would be applied to
(zeronumber) rather than (&zeronumber) . &zeronumber would seem to
mean "the address of a null pointer" which doesn't make sense. I'm
basically confused by the ampersand in front of zeronumber.

>
the address of an object is distinct from its value.'zeronumb er' is
not a pointer ,it is an integer initialized to zero.'&zeronumb er' is a
pointer addressing the location of an integer which is named as
'zeronumber' ,since it is the address of a named object it cn not be
null.Here is the definition of a pointer initailized to null:
>
int * intptr=0;
>
cheers,
FM.

Thanks, Terminator. I'm fairly sure the author wants to apply a
function to the null pointer.

>From what you're saying, I've discovered a bug!

Paul Epstein

[werasm]

Re: basic pointer code

On Oct 28, 10:16 am, pauldepst...@at t.net wrote:

Thanks, Terminator. I'm fairly sure the author wants to apply a
function to the null pointer.

I see no NULL pointer in the code presented, I only
see an integer that is initialized to the value zero.

The pointer passed to the function is perfectly valid
and not zero because the value of the pointer and the
value of the integer are two distinct things. Why the
author of the function chose a pointer as argument
is a different matter on which I won't even begin
to speculate.

Regards,

Werner

[pauldepstein@att.net]

Re: basic pointer code

On Oct 29, 4:02 am, werasm <wer...@gmail.c omwrote:

On Oct 28, 10:16 am, pauldepst...@at t.net wrote:
>

Thanks, Terminator. I'm fairly sure the author wants to apply a
function to the null pointer.

>
I see no NULL pointer in the code presented, I only
see an integer that is initialized to the value zero.
>
The pointer passed to the function is perfectly valid
and not zero because the value of the pointer and the
value of the integer are two distinct things. Why the
author of the function chose a pointer as argument
is a different matter on which I won't even begin
to speculate.
>
Regards,
>
Werner

The code is actually fine, and I jumped to conclusions in suspecting a
mistake. If you look at the freeware of xlw, you will see that there
are functions applied to uninitialised variables, via pointers to
those variables. I found that confusing at first. The author of the
code was writing functions that work with xlw. xlw uses pointers to
the addresses of uninitialised ints and doubles. The author could
have said int x; and then used &x.

Paul Epstein