Re: [Tinycc-devel] Tinycc-devel Digest, Vol 103, Issue 1

[Thomas Preud'homme]

Le mercredi 2 novembre 2011 17:29:13, Robert Clausecker a écrit :
> Am Mittwoch, den 02.11.2011, 12:00 -0400 schrieb Ben Bacarisse
> 
> > > It seems that I discovered a bug in tcc. ANSI C allows declaration
> > 
> > of
> > 
> > > prototypes containing function pointers like this:
> > >         void traverse(mystruct_t*, void(mycontent_t*));
> > > 
> > > tcc currently rejects this giving an error "')' expected". This
> > > 
> > > equivalent prototype works:
> > >         void traverse(mystruct_t*,void(*)(mycontent_t*));
> > > 
> > > Is this a bug or a feature?
> > 
> > The two prototypes are not equivalent.  The first is a syntax error
> > but
> > the second one is fine -- provided you wanted to pass a pointer to a
> > function that takes a mycontent_t pointer and returns nothing.
> 
> I asked some folks on #c on freenode and they told me to tell you that
> section 3.5.4.3, paragraph 9 of the C89 standard specifies that this is
> allowed. (Why else would both gcc and clang allow the first declaration
> with or without the -std=c89 or -ansi flag?) Quote:
> 
>         For each parameter declared with function or array type, its
>         type for these comparisons is the one that results from
>         conversion to a pointer type, as in $3.7.1.
This seems to correspond to §15 in section 6.7.5.3 in C99 standard. Since C99 
is easier to find online, I believe it's worth mentionning.
> 
> I am not an expert on the C spec, but please have a look at it.
> 
> Here is an easier testcase that compiles:
> 
>         int foo(int,int,int(int,int));
>         int foo(int a,int b,int f(int,int)) { return f(a,b); }
> 
> Yours, Robert Clausecker
> 
> 
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