printf("%d", INT_MAX);

**Yevgen Muntyan** · Mar 14 '07, 05:35 PM

Re: printf("%d ", INT_MAX);

Yevgen Muntyan wrote:

Hey,
>
It was mentioned elsewhere that printf("%d", INT_MAX);
is implementation-defined. Why? Is it because INT_MAX
value is implementation-defined so output depends
on implementation, or is it something more subtle so
that output of the following is also implementation-defined:
>
if (INT_MAX == 65535)
printf("%d", INT_MAX);
else
printf("%d", 65535);

Um, I again made it overcomplicated . Is this implementation-defined:

printf("%d\n", 65535);

(if \n matters, then we print \n after the first piece of code too,
it's there in main()).

Yevgen

**Yevgen Muntyan** · Mar 14 '07, 05:45 PM

Re: printf("%d ", INT_MAX);

Yevgen Muntyan wrote:

Yevgen Muntyan wrote:

>Hey,
>>
>It was mentioned elsewhere that printf("%d", INT_MAX);
>is implementation-defined. Why? Is it because INT_MAX
>value is implementation-defined so output depends
>on implementation, or is it something more subtle so
>that output of the following is also implementation-defined:
>>
>if (INT_MAX == 65535)
> printf("%d", INT_MAX);
>else
> printf("%d", 65535);

>
Um, I again made it overcomplicated . Is this implementation-defined:
>
printf("%d\n", 65535);

After consulting the standard, the above should be

printf("%d\n", 32767);

Oh well.

Yevgen

**Eric Sosman** · Mar 14 '07, 05:55 PM

Re: printf("%d ", INT_MAX);

Yevgen Muntyan wrote On 03/14/07 13:29,:

Yevgen Muntyan wrote:
>

>>Yevgen Muntyan wrote:
>>

>>>Hey,
>>>
>>>It was mentioned elsewhere that printf("%d", INT_MAX);
>>>is implementation-defined. Why? Is it because INT_MAX
>>>value is implementation-defined so output depends
>>>on implementation, or is it something more subtle so
>>>that output of the following is also implementation-defined:
>>>
>>>if (INT_MAX == 65535)
>> printf("%d", INT_MAX);
>>>else
>> printf("%d", 65535);

>>
>>Um, I again made it overcomplicated . Is this implementation-defined:
>>
>>printf("%d\n" , 65535);

>
>
After consulting the standard, the above should be
>
printf("%d\n", 32767);

It seems there are several questions here.

The value of INT_MAX is implementation-defined, so the
output produced by printf("%d\n", INT_MAX) is implementation-
defined. There is nothing "wrong" with the operation, but
a strictly-conforming program must not perform it.

The effect of printf("%d\n", 65535) is implementation-
UNdefined (if I may coin a term). If the implementation-
defined value of INT_MAX is >= 65535, then the output is
well defined. If INT_MAX < 65535, the constant 65535 is
of type unsigned int and the behavior is undefined because
"%d" requires a signed int. Hence, it is implementation-
defined whether the behavior is well defined or undefined.

The effect of printf("%d\n", 32767) is the same on all
hosted implementations (barring I/O errors).

--
Eric.Sosman@sun .com

**Yevgen Muntyan** · Mar 14 '07, 06:15 PM

Re: printf("%d ", INT_MAX);

Eric Sosman wrote:

Yevgen Muntyan wrote On 03/14/07 13:29,:

>Yevgen Muntyan wrote:
>>

>>Yevgen Muntyan wrote:
>>>
>>>Hey,
>>>>
>>>It was mentioned elsewhere that printf("%d", INT_MAX);
>>>is implementation-defined. Why? Is it because INT_MAX
>>>value is implementation-defined so output depends
>>>on implementation, or is it something more subtle so
>>>that output of the following is also implementation-defined:
>>>>
>>>if (INT_MAX == 65535)
>>> printf("%d", INT_MAX);
>>>else
>>> printf("%d", 65535);
>>Um, I again made it overcomplicated . Is this implementation-defined:
>>>
>>printf("%d\n" , 65535);

>>
>After consulting the standard, the above should be
>>
>printf("%d\n ", 32767);

>
It seems there are several questions here.
>
The value of INT_MAX is implementation-defined, so the
output produced by printf("%d\n", INT_MAX) is implementation-
defined. There is nothing "wrong" with the operation, but
a strictly-conforming program must not perform it.

Sure.

The effect of printf("%d\n", 65535) is implementation-
UNdefined (if I may coin a term). ...

I thought (wrongly) 65535 was minimal value for INT_MAX.

[snip]

The effect of printf("%d\n", 32767) is the same on all
hosted implementations (barring I/O errors).

And this is what I asked about. I wanted to make sure there
is nothing special about passing INT_MAX as int to a variadic
function or something.
This printf thing was mentioned in connection to another instance
of implementation-defined behavior, where any behavior other
than the "right" one would break code in a serious way, so I wanted
to clarify if this INT_MAX is a usual pedant's story or something
serious.

Thanks,
Yevgen

**Eric Sosman** · Mar 14 '07, 06:45 PM

Re: printf("%d ", INT_MAX);

Yevgen Muntyan wrote On 03/14/07 13:59,:

Eric Sosman wrote:

> The effect of printf("%d\n", 32767) is the same on all
>>hosted implementations (barring I/O errors).

>
>
And this is what I asked about. I wanted to make sure there
is nothing special about passing INT_MAX as int to a variadic
function or something.

No, nothing special. INT_MAX must expand to an expression
whose type is `int'; an expansion with the right value but
some other type would be wrong. Since INT_MAX is already an
`int', no promotions occur. Similarly, `32767' is already an
`int' and nothing happens to it.

This printf thing was mentioned in connection to another instance
of implementation-defined behavior, where any behavior other
than the "right" one would break code in a serious way, so I wanted
to clarify if this INT_MAX is a usual pedant's story or something
serious.

Neither, I think, since there's nothing wrong with it.
My point about printf("%d\n", 65535) is purest pedantry, but
printf("%d\n", INT_MAX) is beyond reproach (despite not being
strictly conforming).

--
Eric.Sosman@sun .com

**CBFalconer** · Mar 15 '07, 12:35 AM

Re: printf("%d ", INT_MAX);

Yevgen Muntyan wrote:

>

.... snip ...

>
Um, I again made it overcomplicated . Is this implementation-defined:
>
printf("%d\n", 65535);

Yes, because there is no guarantee that 65535 is an int. It may be
a long int. It is outside the guaranteed range of an int.

--
Chuck F (cbfalconer at maineline dot net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home .att.net>

--
Posted via a free Usenet account from http://www.teranews.com

**Yevgen Muntyan** · Mar 15 '07, 01:15 AM

Re: printf("%d ", INT_MAX);

CBFalconer wrote:

Yevgen Muntyan wrote:
... snip ...

>Um, I again made it overcomplicated . Is this implementation-defined:
>>
>printf("%d\n ", 65535);

>
Yes, because there is no guarantee that 65535 is an int. It may be
a long int. It is outside the guaranteed range of an int.

It's not implementation-defined if INT_MAX is less than 65535, is it?
Anyway, as you probably know, it was a wrong question.

Yevgen

**Jack Klein** · Mar 15 '07, 02:55 AM

Re: printf("%d ", INT_MAX);

On Wed, 14 Mar 2007 17:24:02 GMT, Yevgen Muntyan
<muntyan.remove this@tamu.eduwr ote in comp.lang.c:

Hey,
>
It was mentioned elsewhere that printf("%d", INT_MAX);
is implementation-defined. Why? Is it because INT_MAX
value is implementation-defined so output depends
on implementation, or is it something more subtle so
that output of the following is also implementation-defined:
>
if (INT_MAX == 65535)
printf("%d", INT_MAX);
else
printf("%d", 65535);
>
Thanks,
Yevgen

Aside from newline issue, that you posted a correction to, the snippet
above, when packaged within an appropriate program with inclusion of
<stdio.hand <limits.his not strictly conforming, as pointed out in
4 p5 of the C99 standard:

"A strictly conforming program shall use only those features of the
language and library specified in this International Standard. It
shall not produce output dependent on any unspecified, undefined, or
implementation-defined behavior, and shall not exceed any minimum
implementation limit."

--
Jack Klein
Home: http://JK-Technology.Com
FAQs for
comp.lang.c http://c-faq.com/
comp.lang.c++ http://www.parashift.com/c++-faq-lite/
alt.comp.lang.l earn.c-c++

404 Not Found

http://www.contrib.andrew.cmu.edu/~ajo/docs/FAQ-acllc.html

**Kenneth Brody** · Mar 15 '07, 06:25 PM

Re: printf("%d ", INT_MAX);

Eric Sosman wrote:
[...]

The value of INT_MAX is implementation-defined, so the
output produced by printf("%d\n", INT_MAX) is implementation-
defined. There is nothing "wrong" with the operation, but
a strictly-conforming program must not perform it.

[...]

So, technically speaking, the following is non-conforming?

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

int main(void)
{
printf("INT_MAX is %d\n",INT_MAX);
return(EXIT_SUC CESS);
}

--
+-------------------------+--------------------+-----------------------+
| Kenneth J. Brody | www.hvcomputer.com | #include |
| kenbrody/at\spamcop.net | www.fptech.com | <std_disclaimer .h|
+-------------------------+--------------------+-----------------------+
Don't e-mail me at: <mailto:ThisIsA SpamTrap@gmail. com>

**Ben Pfaff** · Mar 15 '07, 06:35 PM

Re: printf("%d ", INT_MAX);

Kenneth Brody <kenbrody@spamc op.netwrites:

So, technically speaking, the following is non-conforming?
>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
>
int main(void)
{
printf("INT_MAX is %d\n",INT_MAX);
return(EXIT_SUC CESS);
}

It's not strictly conforming, but it is conforming:

A strictly conforming program shall use only those features
of the language and library specified in this International
Standard.2) It shall not produce output dependent on any
unspecified, undefined, or implementation-defined behavior,
and shall not exceed any minimum implementation limit.

...

A conforming program is one that is acceptable to a
conforming implementation. 4)

...

4) Strictly conforming programs are intended to be maximally
portable among conforming implementations . Conforming
programs may depend upon nonportable features of a
conforming implementation.
--
"Large amounts of money tend to quench any scruples I might be having."
-- Stephan Wilms

**Eric Sosman** · Mar 15 '07, 07:05 PM

Re: printf("%d ", INT_MAX);

Kenneth Brody wrote On 03/15/07 10:46,:

Eric Sosman wrote:
[...]
>

> The value of INT_MAX is implementation-defined, so the
>>output produced by printf("%d\n", INT_MAX) is implementation-
>>defined. There is nothing "wrong" with the operation, but
>>a strictly-conforming program must not perform it.

>
[...]
>
So, technically speaking, the following is non-conforming?
>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
>
int main(void)
{
printf("INT_MAX is %d\n",INT_MAX);
return(EXIT_SUC CESS);
}

It is conforming, but not strictly conforming. From
section 4, paragraphs 5 and 7 and footnote 4:

A /strictly conforming program/ [...] shall not
produce output dependent on [...] implementation-
defined behavior [...]

A /conforming program/ is one that is acceptable to
a conforming implementation. 4)

4) Strictly conforming programs are intended to be
maximally portable among conforming implementations .
Conforming programs may depend upon nonportable
features of a conforming implementation.

The distinction between strictly conforming and conforming
programs is one that the Standard is pretty much forced to make,
but it has always seemed to me that the Standard's definition
of strict conformance is too restrictive to be as useful as it
should be. When a program like Kenneth Brody's turns out not
to be strictly conforming, I think the baby has been thrown out
with the bath water. But I have no better definition to offer,
so I can't complain very convincingly!

When the ANSI Standard was young there used to be a lot of
discussions in c.l.c. about just what "strictly conforming" and
"conforming " were, with reams of writing claiming to explicate
the Real Intent of the writers, sort of like lawyers trying to
find an inherent right to broadband in the U.S. Constitution.
Among these cacophonies of opinion one would occasionally find
"proofs" of the non-existence of strictly conforming programs,
or of "non-silly" strictly conforming programs. For example:

- An S.C. program cannot use the #include directive except
for the headers described in the Standard itself, because
the search algorithm for other headers is implementation-
defined. Since the effect of #include "foo.h" is defined
by the implementation, a program that uses it depends on
implementation-defined behavior.

- An S.C. program cannot terminate, because its termination
status is part of its "output" and has an implementation-
defined form, hence a program that terminates produces
output that depends on implementation-defined behavior.

- An S.C. program cannot produce any output at all, because
the output is rendered in an implementation-defined
character encoding.

- An S.C. program cannot allow its output to be affected by
the success or failure of any particular malloc() call,
because the conditions under which malloc() succeeds or
fails are implementation-defined. An S.C. program can
call malloc(), but even if every single malloc() call
returns NULL its output must be unchanged.

.... and so on. Some arguments of this sort were probably raised
for the purpose of amusement (like the fanciful descriptions of
undefined behavior that used to be popular; "demons will fly from
your nose" was just one of many). Some were probably raised to
mock the newly-minted Standard. Some may have been intended as
serious criticisms. All seem to me to have had tiny grains of
truth (however distorted), enough grains to suggest that this
part of the Standard may have feet of slowly-crumbling clay.

--
Eric.Sosman@sun .com

**pete** · Mar 16 '07, 03:45 AM

Re: printf("%d ", INT_MAX);

Eric Sosman wrote:

>
Kenneth Brody wrote On 03/15/07 10:46,:

Eric Sosman wrote:
[...]

The value of INT_MAX is implementation-defined, so the
>output produced by printf("%d\n", INT_MAX) is implementation-
>defined. There is nothing "wrong" with the operation, but
>a strictly-conforming program must not perform it.

[...]

So, technically speaking, the following is non-conforming?

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

int main(void)
{
printf("INT_MAX is %d\n",INT_MAX);
return(EXIT_SUC CESS);
}

>
It is conforming, but not strictly conforming. From
section 4, paragraphs 5 and 7 and footnote 4:
>
A /strictly conforming program/ [...] shall not
produce output dependent on [...] implementation-
defined behavior [...]
>
A /conforming program/ is one that is acceptable to
a conforming implementation. 4)
>
4) Strictly conforming programs are intended to be
maximally portable among conforming implementations .
Conforming programs may depend upon nonportable
features of a conforming implementation.
>
The distinction between strictly conforming and conforming
programs is one that the Standard is pretty much forced to make,
but it has always seemed to me that the Standard's definition
of strict conformance is too restrictive to be as useful as it
should be. When a program like Kenneth Brody's turns out not
to be strictly conforming, I think the baby has been thrown out
with the bath water. But I have no better definition to offer,
so I can't complain very convincingly!

Kenneth Brody's program
is what the C standard calls "a correct program".

N869
4. Conformance
[#3] A program that is correct in all other aspects,
operating on correct data, containing unspecified behavior
shall be a correct program and act in accordance with
5.1.2.3.

Even though the term isn't used that often on this newsgroup,
"correct programs"
is what I consider this newsgroup to be mostly about.

Ben Pfaff likes the term "correct program".

"When I wrote my earlier article in this thread, I knew that
"strictly conforming" was not a perfect term, but I didn't have a
better one and didn't feel like adding a lot of qualifiers or an
extended explanation."

429

http://groups.google.com/group/comp.lang.c/msg/b9807153d40349c7

--
pete

**CBFalconer** · Mar 16 '07, 05:05 PM

Re: printf("%d ", INT_MAX);

Eric Sosman wrote:

>

.... snip ...

>
The distinction between strictly conforming and conforming
programs is one that the Standard is pretty much forced to make,
but it has always seemed to me that the Standard's definition
of strict conformance is too restrictive to be as useful as it
should be. When a program like Kenneth Brody's turns out not
to be strictly conforming, I think the baby has been thrown out
with the bath water. But I have no better definition to offer,
so I can't complain very convincingly!

I don't think a strictly conforming *program* exists, but many
strictly conforming *routines* do exist. I.E. those routines that
can be implemented anywhere.

--
Chuck F (cbfalconer at maineline dot net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home .att.net>

--
Posted via a free Usenet account from http://www.teranews.com

**Keith Thompson** · Mar 16 '07, 06:25 PM

Re: printf("%d ", INT_MAX);

CBFalconer <cbfalconer@yah oo.comwrites:

Eric Sosman wrote:

>>

... snip ...

>>
> The distinction between strictly conforming and conforming
>programs is one that the Standard is pretty much forced to make,
>but it has always seemed to me that the Standard's definition
>of strict conformance is too restrictive to be as useful as it
>should be. When a program like Kenneth Brody's turns out not
>to be strictly conforming, I think the baby has been thrown out
>with the bath water. But I have no better definition to offer,
>so I can't complain very convincingly!

>
I don't think a strictly conforming *program* exists, but many
strictly conforming *routines* do exist. I.E. those routines that
can be implemented anywhere.

The standard doesn't talk about strictly conforming routines, and I
think the phrase "strictly conforming" is so narrowly defined that we
should avoid using it other than in the sense specified in the
standard. The idea of "routines that can be implemented anywhere" is
certainly a useful one, though; perhaps that's the same as "routines
(function?) that can potentially be used in a strictly conforming
program".

There's some controversy about what is or is not a "strictly
conforming program", but here's a program that I think meets the
definition unambiguously:

int main(void) { return 0; }

--
Keith Thompson (The_Other_Keit h) kst-u@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <* <http://users.sdsc.edu/~kst>
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

printf("%d", INT_MAX);

printf("%d", INT_MAX);

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