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Groups > comp.lang.c > #142663
| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: C Translator |
| Date | 2019-03-31 22:37 +0100 |
| Organization | A noiseless patient Spider |
| Message-ID | <871s2m9140.fsf@bsb.me.uk> (permalink) |
| References | (15 earlier) <jG1oE.282641$kh.152691@fx27.am4> <877ecf9lyv.fsf@bsb.me.uk> <dW4oE.682614$ao.267556@fx32.am4> <q7r3rg$ua7$1@dont-email.me> <lZ8oE.867468$iV1.117974@fx25.am4> |
Bart <bc@freeuk.com> writes:
> With input of:
>
> static int fred(void);
>
> ... all C compilers pass it with no warnings
That's correct. A function need only be defined if it is used.
> (using default options in all cases)
Please stop doing this. At least ask for the code to be treated as C
(e.g. -std=c11 for gcc) rather than whatever language the compiler is
pushing.
> and treat it as an import. Is my translator wrong, or those compilers?
That I don't know, because (and I know you probably won't believe me), I
don't know what "treat it as an import" means. I say a bit more about
that later on.
> With input of:
>
> int abc;
>
> my translator gives output of:
>
> global int32 abc
>
> (ie. assumes it is exported.). However, 'int abc;' is commonly used in
> C programs to declare that 'abc' is imported from elsewhere. This
> generally gets sorted out in a linker (which either fixes the problem,
> or reports a multiple definition).
This again! I should assume you don't remember. If you did, you would
explain what is going on, yes?
> I assume you're quite good at this stuff. So in each of these complete
> programs of my examples, is fred or abc local, exported or imported,
> or is there a bug in the program, or is there a bug in every C
> compiler I tried:
>
> int fred(void);
>
> static int fred(void);
>
> int abc;
I think there are some typos in the question, but as I read it, if each
line is taken as a complete program, they are all undefined. The
compiler can do anything it likes because there is no main function.
With a null main, all of these
int fred(void); int main(void) {}
static int fred(void); int main(void) {}
int abc; int main(void) {}
should compile and none requires a diagnostic. Since the named entities
are not used, the implementation can ignore them, but in so far as it
makes any sense to say so in a complete program, the two 'fred's and
'abc' have external, internal and external linkage respectively.
Adding a main that uses the declared entities we can say more:
int fred(void); int main(void) { return fred(); }
Undefined. A function is used but there is no definition of it. fred
has external linkage (I don't know if that is local, exported or
imported -- you could tell me).
static int fred(void); int main(void) { return fred(); }
Also undefined, but fred has internal linkage this time.
int abc; int main(void) { return abc; }
Fine. The program returns 0 (a "successful termination status") to the
host environment. abc has external linkage, though it makes no
difference since this is a complete program.
--
Ben.
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C Translator Bart <bc@freeuk.com> - 2019-03-28 16:16 +0000
Re: C Translator Bart <bc@freeuk.com> - 2019-03-29 00:01 +0000
Re: C Translator Robert Wessel <robertwessel2@yahoo.com> - 2019-03-28 20:31 -0500
Re: C Translator Keith Thompson <kst-u@mib.org> - 2019-03-28 19:02 -0700
Re: C Translator Bart <bc@freeuk.com> - 2019-03-29 02:34 +0000
Re: C Translator David Brown <david.brown@hesbynett.no> - 2019-03-29 10:58 +0100
Re: C Translator Bart <bc@freeuk.com> - 2019-03-29 12:47 +0000
Re: C Translator David Brown <david.brown@hesbynett.no> - 2019-03-29 14:57 +0100
Re: C Translator Bart <bc@freeuk.com> - 2019-03-29 14:57 +0000
Re: C Translator fir <profesor.fir@gmail.com> - 2019-03-29 15:08 -0700
Re: C Translator fir <profesor.fir@gmail.com> - 2019-03-29 15:42 -0700
Re: C Translator scott@slp53.sl.home (Scott Lurndal) - 2019-03-29 15:16 +0000
Re: C Translator Bart <bc@freeuk.com> - 2019-03-29 15:30 +0000
Re: C Translator fir <profesor.fir@gmail.com> - 2019-03-29 14:47 -0700
Re: C Translator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-29 10:42 +0000
Re: C Translator Bart <bc@freeuk.com> - 2019-03-29 11:57 +0000
Re: C Translator Bart <bc@freeuk.com> - 2019-03-29 13:04 +0000
Re: C Translator David Brown <david.brown@hesbynett.no> - 2019-03-29 14:58 +0100
Re: C Translator Bart <bc@freeuk.com> - 2019-03-29 14:29 +0000
Re: C Translator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-29 20:06 +0000
Re: C Translator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-29 20:02 +0000
Re: C Translator Bart <bc@freeuk.com> - 2019-03-29 21:10 +0000
Re: C Translator nobody@example.org (Scott) - 2019-03-30 04:52 +0000
Re: C Translator Bart <bc@freeuk.com> - 2019-03-30 11:03 +0000
Re: C Translator nobody@example.org (Scott) - 2019-03-30 16:17 +0000
Re: C Translator Bart <bc@freeuk.com> - 2019-03-30 18:36 +0000
Re: C Translator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-30 20:32 +0000
Re: C Translator Bart <bc@freeuk.com> - 2019-03-30 22:44 +0000
Re: C Translator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-31 03:23 +0100
Re: C Translator Bart <bc@freeuk.com> - 2019-03-31 12:39 +0100
Re: C Translator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-31 15:07 +0100
Re: C Translator Bart <bc@freeuk.com> - 2019-03-31 16:21 +0100
Re: C Translator David Brown <david.brown@hesbynett.no> - 2019-03-31 21:19 +0200
Re: C Translator Bart <bc@freeuk.com> - 2019-03-31 20:58 +0100
Re: C Translator Ike Naar <ike@iceland.freeshell.org> - 2019-03-31 20:33 +0000
Re: C Translator Bart <bc@freeuk.com> - 2019-03-31 22:06 +0100
Re: C Translator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-31 22:37 +0100
Re: C Translator Bart <bc@freeuk.com> - 2019-03-31 23:33 +0100
Re: C Translator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-04-01 02:35 +0100
Re: C Translator David Brown <david.brown@hesbynett.no> - 2019-04-01 11:33 +0200
Re: C Translator David Brown <david.brown@hesbynett.no> - 2019-03-31 23:54 +0200
Re: C Translator Bart <bc@freeuk.com> - 2019-04-01 02:16 +0100
Re: C Translator Ike Naar <ike@iceland.freeshell.org> - 2019-04-01 06:42 +0000
Re: C Translator David Brown <david.brown@hesbynett.no> - 2019-04-01 11:35 +0200
Re: C Translator Bart <bc@freeuk.com> - 2019-04-01 16:54 +0100
Re: C Translator Bart <bc@freeuk.com> - 2019-04-01 21:01 +0100
Re: C Translator Keith Thompson <kst-u@mib.org> - 2019-04-01 13:41 -0700
Re: C Translator Bart <bc@freeuk.com> - 2019-04-01 22:40 +0100
Re: C Translator Keith Thompson <kst-u@mib.org> - 2019-04-01 16:25 -0700
Re: C Translator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-04-02 00:50 +0100
Re: C Translator Keith Thompson <kst-u@mib.org> - 2019-04-01 17:45 -0700
Re: C Translator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-04-02 11:28 +0100
Re: C Translator David Brown <david.brown@hesbynett.no> - 2019-04-02 13:18 +0200
Re: C Translator Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-04-02 19:15 +0000
Re: C Translator Bart <bc@freeuk.com> - 2019-04-02 21:14 +0100
Re: C Translator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-04-02 13:28 +0100
Re: C Translator David Brown <david.brown@hesbynett.no> - 2019-04-02 10:49 +0200
Re: C Translator Bart <bc@freeuk.com> - 2019-04-02 01:58 +0100
Re: C Translator Keith Thompson <kst-u@mib.org> - 2019-04-01 19:13 -0700
Re: C Translator Bart <bc@freeuk.com> - 2019-04-02 11:13 +0100
Re: C Translator David Brown <david.brown@hesbynett.no> - 2019-04-02 13:49 +0200
Re: C Translator Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-04-02 05:15 -0700
Re: C Translator Bart <bc@freeuk.com> - 2019-04-02 14:50 +0100
Re: C Translator David Brown <david.brown@hesbynett.no> - 2019-04-02 16:06 +0200
Re: C Translator David Brown <david.brown@hesbynett.no> - 2019-04-02 16:05 +0200
Re: C Translator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-04-02 00:11 +0100
Re: C Translator David Brown <david.brown@hesbynett.no> - 2019-04-02 10:35 +0200
Re: C Translator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-04-02 00:06 +0100
Re: C Translator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-31 21:36 +0100
Re: C Translator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-31 16:32 +0100
Re: C Translator Bart <bc@freeuk.com> - 2019-03-30 00:37 +0000
Re: C Translator Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-03-30 01:00 +0000
Re: C Translator fir <profesor.fir@gmail.com> - 2019-03-30 03:37 -0700
Re: C Translator fir <profesor.fir@gmail.com> - 2019-03-30 06:15 -0700
Re: C Translator James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-03-29 07:49 -0700
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