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Re: Problem building vector/reim_source.c


On Sun, Aug 19, 2001 at 11:53:37AM +0100, Brian Gough wrote:
> gsl-discuss@lists.thewrittenword.com writes:
>  > >   {
>  > >      gsl_vector_long_double_const_view  view =  { { 0 , 0 , 0 , 0 } };
>  > >     (( gsl_vector_long_double_view  *)(&view))->vector = s;
>  > >     return view;
>  > >   }
>  > > }
>  > > 
>  > > So, the Solaris C compiler isn't allowing you to throw away the
>  > > const'ness of view (seems correct to me). I tried compiling with the
>  > > native compilers on Tru64 UNIX, IRIX, HP, and AIX and they all accept
>  > > the construct above.
>  > 
>  > Actually, it's complaining about "return view".
> 
> Right. 
> 
> I believe the Solaric C compiler is incorrect on this point.
> 
> I should have added this to the release notes but forgot (now added).

I've opened a problem report with Sun and gave them a small test case
to reproduce the bug. I'll forward your info below if they need
convincing.

> For more info see my recent post on comp.std.c and Eric Rose's
> and my posts on comp.lang.c.moderated.
> 
> I think they are misinterpreting section 6.6.6.4,
> 
>     If a return statement with an expression is executed the value of
>     the expression is returned to the caller as the value of the
>     function call expression.  If the expression has a type different
>     from that of the function in which it appears, it is converted as
>     if it were assigned to an object of that type.
> 
> It looks like they are applying the second rule, since the '=' sign in
> the error message indicates assignment.  This results in an error,
> since the return type is a struct containing a const element.
> However, the expression type is the same as the function type, so this
> rule should not be applied here.
> 
> regards
> Brian Gough

-- 
albert chin (china@thewrittenword.com)


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