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Re: Call to a function

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Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
> Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:
>> Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
>> [...]
>>> The point isn't quite the same.  The C standard explicitly says
>>> integers may be converted to any pointer type.  The C standard
>>> does not say that a pointer to an object type may be converted
>>> to a pointer to function type.  Every implementation is within
>>> its rights to reject any program whose static text includes[*] a
>>> cast from a pointer to an object type to a pointer to function
>>> type, regardless of whether the cast has any chance of being
>>> executed.
>>>
>>> [*] meaning, still present as source of any preprocessor
>>> conditionals have been processed, etc.
>>
>> I disagree.  (I think we've discussed this before.)
>>
>> Concretely, I believe that this program violates no syntax error
>> or constraint.  It includes code whose behavior would be undefined
>> if it were executed, but the `if (0)` prevents that.
>>
>> On what basis do you think a conforming implementation may reject
>> it?
>
> First let me ask a question.  Does the C standard allow an
> implementation to reject any program that is not strictly
> conforming?

Not just for that reason.

This program:

#include <stdio.h>
int main(void) {
    printf("%zu\n", sizeof (int));
}

is not strictly conforming, since it depends on the
implementation-defined size of int.  A hosted implementation that
rejected it would violate 4p3:

    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.

(A perverse implementation could claim that it exceeds its capacity, but
I think we can ignore that.)

What is your answer to your own question?

And I hope we're not going to go back and forth too many times before
you answer mine.

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Will write code for food.
void Void(void) { Void(); } /* The recursive call of the void */

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Re: Call to a function Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-10-24 20:54 -0700
  Re: Call to a function Richard Damon <richard@damon-family.org> - 2023-10-24 21:27 -0700
  Re: Call to a function Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-10-24 21:58 -0700
  Re: Call to a function James Kuyper <jameskuyper@alumni.caltech.edu> - 2023-10-25 01:13 -0400
    Re: Call to a function Kaz Kylheku <864-117-4973@kylheku.com> - 2023-10-25 06:46 +0000
  Re: Call to a function Kaz Kylheku <864-117-4973@kylheku.com> - 2023-10-25 06:37 +0000

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