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From: Janis Papanagnou <janis_papanagnou+ng@hotmail.com>
Newsgroups: comp.lang.c
Subject: Re: Whaddaya think?
Date: Mon, 17 Jun 2024 09:22:58 +0200
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On 17.06.2024 08:21, James Kuyper wrote:
> On 6/17/24 01:41, Janis Papanagnou wrote:
>> On 16.06.2024 22:32, Keith Thompson wrote:
>>> Janis Papanagnou <janis_papanagnou+ng@hotmail.com> writes:
>>>> [...] K&R at
>>>> least seems to say that 'void' can only be declared for the
>>>> return type of functions that do not return anything.
>>>> [...]
>>>
>>> No version of C has ever permitted "void main" except when an
>>> implementation documents and permits it.  [...]
>>
>> I cannot comment on main() being handled differently than
>> other C functions. I was just quoting my old copy of K&R.
> 
> It is handled differently. Your own functions can be declared in a wide
> variety of ways, so long as the declaration that is relevant to function
> designator in a function call is compatible with the definition of the
> function that it designates.
> C standard library functions can only be declared in ways compatible
> with the specifications in the C standard.
> main(), on the other hand, is unique, in that you have two incompatible
> choices of how to define it, and an implementation can designate
> additional choices. You can define main() in any way compatible with one
> of the options supported by your implementation; but portable code
> should define it only in one of the two ways specified by the C standard.
> K&R is long obsolete; up-to-date drafts of the standard that are almost
> identical to the latest version of the standard are free and easily
> available.
> 
>> I don't understand what you mean with "no version of C has
>> ever permitted", given that my C compiler doesn't complain.
> 
> He wrote "No version of C has ever permitted "void main" except when an
> implementation documents and permits it." Note that he is talking about
> versions of the standard, not versions of any particular implementation
> of C. If your C compiler "documents and permits" "void main", then it
> certainly shouldn't complain about it. However, since the C standard
> does not mandate support for void main, you've no guarantee of
> portability of code that uses void main to other implementations of C.
> 

Re portability: Of course there's other requirements for portable
and generally for professional code. I wrote a lot more professional
code in C++ than in C but the same requirements hold. Defining the
version of the standard, the supported platforms, activation of high
warning levels - we wanted our code free of warnings! -, and whatnot.

Janis