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Risking to invoke flames from one Tom St Denis of Ottawa

Is there any guarantee that, say,
sizeof(int) == sizeof(unsigned int)
sizeof(long) > sizeof(char) ?

Thanks,
Ark

ark wrote:
>
> Is there any guarantee that, say,
> sizeof(int) == sizeof(unsigned int)
> sizeof(long) > sizeof(char) ?

I don't believe the standard guarantees that either is true.

--
Russell Hanneken

Remove the 'g' from my address to send me mail.

ark wrote:

> Is there any guarantee that, say,
> sizeof(int) == sizeof(unsigned int)

Yes.

> sizeof(long) > sizeof(char) ?

No. BTW, sizeof(char) == 1 by definition.

However, sizeof(long) == 1, which I think implies sizeof(int) == 1,
would break several very common idioms, e.g.

int ch;
while ((ch = getchar()) != EOF) { ... }

because EOF is supposed to be a value which is different from all
'unsigned char' values. That is only possible when 'int' is wider
than 'unsigned char'.

Personally I've never seen a program which worred about this
possibility, though I suppose such programs exist. It might
be different with freestanding implementations (implementations
which do not use the C library, so getchar() is no problem).

--
Hallvard

"ark" <> writes:

> Is there any guarantee that, say,
> sizeof(int) == sizeof(unsigned int)

Yes.

> sizeof(long) > sizeof(char) ?

No.
--
"Your correction is 100% correct and 0% helpful. Well done!"
--Richard Heathfield

Russell Hanneken <> writes:

> ark wrote:
>> Is there any guarantee that, say,
>> sizeof(int) == sizeof(unsigned int)
>> sizeof(long) > sizeof(char) ?
>
> I don't believe the standard guarantees that either is true.

The former, but not the latter, is guaranteed.
--
"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it."
--Brian Kernighan

ark wrote:

> Risking to invoke flames from one Tom St Denis of Ottawa
>
> Is there any guarantee that, say,
> sizeof(int) == sizeof(unsigned int)
> sizeof(long) > sizeof(char)?

Are you aware of the type definitions in <stdint.h>?

Hallvard B Furuseth <h.b.furuseth(nospam)@usit.uio(nospam).no> writes:

> However, sizeof(long) == 1, which I think implies sizeof(int) == 1,

Actually there's no such implication. The range of int is a
subrange of the range of long, but there's no such guarantee on
the size in bytes of these types.

However, it would be a strange system for which sizeof(long) <
sizeof(int). I don't know of any.
--
"...Almost makes you wonder why Heisenberg didn't include postinc/dec operators
in the uncertainty principle. Which of course makes the above equivalent to
Schrodinger's pointer..."
--Anthony McDonald

"Hallvard B Furuseth" <h.b.furuseth(nospam)@usit.uio(nospam).no> wrote in
message news:...
>
> However, sizeof(long) == 1, which I think implies sizeof(int) == 1,
> would break several very common idioms, e.g.
>
> int ch;
> while ((ch = getchar()) != EOF) { ... }
>
> because EOF is supposed to be a value which is different from all
> 'unsigned char' values. That is only possible when 'int' is wider
> than 'unsigned char'.
>
> Personally I've never seen a program which worred about this
> possibility, though I suppose such programs exist. It might
> be different with freestanding implementations (implementations
> which do not use the C library, so getchar() is no problem).
>
> --
> Hallvard

I believe that a 16-bit DSP with a 16-bit byte would have
sizeof(int)==sizeof(short) (and ==1).
- Ark

"E. Robert Tisdale" wrote:
> ark wrote:
>
> > Risking to invoke flames from one Tom St Denis of Ottawa
> >
> > Is there any guarantee that, say,
> > sizeof(int) == sizeof(unsigned int)
> > sizeof(long) > sizeof(char)?
>
> Are you aware of the type definitions in <stdint.h>?

Only implied misinformation from Trollsdale this time. <stdint.h>
is a C99 artifact, and the type defined therein are only defined
when the implementation has suitable types. So you could do
something like:

#if defined(sometype)
#define mytype sometype
#else
#define mytype whatever
#endif

with suitable guards for a C99 system.

--
Chuck F () ()
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home.att.net> USE worldnet address!

In article <>,
"E. Robert Tisdale" <> wrote:

> ark wrote:
>
> > Risking to invoke flames from one Tom St Denis of Ottawa
> >
> > Is there any guarantee that, say,
> > sizeof(int) == sizeof(unsigned int)
> > sizeof(long) > sizeof(char)?
>
> Are you aware of the type definitions in <stdint.h>?

Quite possibly he is aware of them and knows that they have nothing to
do with the question asked.