On Sat, 29 Aug 2009 14:22:40 -0400, Warp wrote:

> Jim Henderson <nos### [at] nospamcom> wrote:
>> Yes, it would be a valid .c file because a library doesn't need to have
>> a main() function.
> 
>   Have you checked that the C standard agrees with you?

I researched a little bit, yes.  By definition, a library is not a 
program, just a collection of functions, and as such, a main function is 
not required (in fact, it could cause problems to have a library with a 
main() function).

Jim

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On Sat, 29 Aug 2009 14:22:40 -0400, Warp wrote:

> Jim Henderson <nos### [at] nospamcom> wrote:
>> Yes, it would be a valid .c file because a library doesn't need to have
>> a main() function.
> 
>   Have you checked that the C standard agrees with you?

Windows programs also don't include a main() function - their entry is 
WinMain() IIRC.

Jim

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On Sat, 29 Aug 2009 20:20:56 +0200, Warp <war### [at] tagpovrayorg> wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> Hence my clarification. It's obviously a valid .h file. But is it a  
>> valid .c file?
>
>   According to gcc, no (although it does compile it nevertheless):
>
> > touch test.c
> > ls -l
>  total 0
>  -rw-r--r-- 1 warp users 0 2009-08-29 21:18 test.c
> > gcc -pedantic -c test.c
>  test.c:1: warning: ISO C forbids an empty source file
>  warp@a8:~/tmp/hops>ls -l
>  total 4
>  -rw-r--r-- 1 warp users   0 2009-08-29 21:18 test.c
>  -rw-r--r-- 1 warp users 684 2009-08-29 21:18 test.o

Not everyone thinks that GCC is right about this. The only relevant part I  
can find in the actual standard is "A source file that is not empty shall  
end in a new-line character" (5.1.1.2.2), which seems to imply that empty  
source files are OK.



-- 
FE

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On Sat, 29 Aug 2009 14:22:40 -0400, Warp wrote:

> Jim Henderson <nos### [at] nospamcom> wrote:
>> Yes, it would be a valid .c file because a library doesn't need to have
>> a main() function.
> 
>   Have you checked that the C standard agrees with you?

And further, a multi-file C program doesn't require that every .c file 
have a main() function defined.  Therefore, having a .c file that has no 
main() function in it *is* valid.

Jim

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On Sat, 29 Aug 2009 20:43:36 +0200, Jim Henderson <nos### [at] nospamcom>  
wrote:
>
> Windows programs also don't include a main() function - their entry is
> WinMain() IIRC.

This of course being a platform-specific, non-standard convenience  
extension.


-- 
FE

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On Sat, 29 Aug 2009 20:50:18 +0200, Fredrik Eriksson wrote:

> On Sat, 29 Aug 2009 20:43:36 +0200, Jim Henderson <nos### [at] nospamcom>
> wrote:
>>
>> Windows programs also don't include a main() function - their entry is
>> WinMain() IIRC.
> 
> This of course being a platform-specific, non-standard convenience
> extension.

Yes, it's defined as a "freestanding" program IIRC.  Point is that you 
can specify a different entry point if desired.

Jim

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Jim Henderson <nos### [at] nospamcom> wrote:
> On Sat, 29 Aug 2009 14:22:40 -0400, Warp wrote:

> > Jim Henderson <nos### [at] nospamcom> wrote:
> >> Yes, it would be a valid .c file because a library doesn't need to have
> >> a main() function.
> > 
> >   Have you checked that the C standard agrees with you?

> I researched a little bit, yes.  By definition, a library is not a 
> program, just a collection of functions, and as such, a main function is 
> not required (in fact, it could cause problems to have a library with a 
> main() function).

  That's not what I meant. I was talking about source files which contain
nothing. The question was whether an empty file is a valid C source file,
to which you responded positively, which is why I asked whether the standard
also says so.

-- 
                                                          - Warp

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On Sat, 29 Aug 2009 15:28:12 -0400, Warp wrote:

> Jim Henderson <nos### [at] nospamcom> wrote:
>> On Sat, 29 Aug 2009 14:22:40 -0400, Warp wrote:
> 
>> > Jim Henderson <nos### [at] nospamcom> wrote:
>> >> Yes, it would be a valid .c file because a library doesn't need to
>> >> have a main() function.
>> > 
>> >   Have you checked that the C standard agrees with you?
> 
>> I researched a little bit, yes.  By definition, a library is not a
>> program, just a collection of functions, and as such, a main function
>> is not required (in fact, it could cause problems to have a library
>> with a main() function).
> 
>   That's not what I meant. I was talking about source files which
>   contain
> nothing. The question was whether an empty file is a valid C source
> file, to which you responded positively, which is why I asked whether
> the standard also says so.

The bit you quoted from what I said specifically had to do with a main() 
function not being needed.  It wasn't clear that you were talking about 
an empty file, I thought you were specifically talking about the lack of 
a main() function, since that's what you quoted.

Though now that you've clarified, I see that it could be read either way.

Jim

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Jim Henderson wrote:
> Though now that you've clarified, I see that it could be read either way.

I anyone else amused that one can start a flame war amongst geeks over an 
empty file? :-)

-- 
   Darren New, San Diego CA, USA (PST)
   Understanding the structure of the universe
    via religion is like understanding the
     structure of computers via Tron.

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On Sat, 29 Aug 2009 17:02:10 -0700, Darren New wrote:

> Jim Henderson wrote:
>> Though now that you've clarified, I see that it could be read either
>> way.
> 
> I anyone else amused that one can start a flame war amongst geeks over
> an empty file? :-)

Oh, yes, I am very amused by this.  :-)

Jim

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