Re: problem with changeset fa917f1f0faf

[Mike Miller]

On Wed, Aug 10, 2016 at 20:51:31 -0400, Ben Abbott wrote:
> > On Aug 10, 2016, at 8:37 PM, Carnë Draug <address@hidden> wrote:
> > 
> > On 11 August 2016 at 00:47, Ben Abbott <address@hidden> wrote:
> >> Carne,
> >> 
> >> I think I’m seeing an error associated with the change below.
> >> 
> >>        http://hg.savannah.gnu.org/hgweb/octave/rev/fa917f1f0faf
> >> 
> >> [...]
> >> 
> >> liboctave/array/MatrixType.cc:530:23: error: assigning to 'double' from 
> >> incompatible type 'complex<double>'
> >>                    d = std::conj (d);
> >>                      ^ ~~~~~~~~~~~~~
> > 
> > How does your compiler handles this?
> > 
> >    #include <iostream>
> >    #include <complex>
> >    #include <typeinfo>
> > 
> >    int main()
> >    {
> >      std::cout << typeid (std::conj (double (5.0))).name() << std::endl;
> >    }
> > 
> > If you get back a complex number, the issue is discussed on DR 1137 [1].
> > You should get back d for double.  I only found this DR number because
> > it's refered on the GCC implementation of conj.
> > 
> > Carnë
> > 
> > [1] https://lwg.github.io/issues/lwg-defects.html#1137
> 
> I’m out of my element … I placed those lines in foo.cc and compiled using 
> Apple’s clang

I took the liberty of testing with clang 3.8 on Debian.

With clang and llvm libc++, I get similar errors about streams and char_traits.

With clang and gcc libstdc++, I get the following:

  address@hidden:~/src$ clang-3.8 -o foo foo.cc
  foo.cc:7:24: error: no matching function for call to 'conj'
    std::cout << typeid (std::conj (double (5.0))).name() << std::endl;
                         ^~~~~~~~~
  
/usr/bin/../lib/gcc/x86_64-linux-gnu/6.1.1/../../../../include/c++/6.1.1/complex:677:5:
 note: candidate template ignored: could not match 
'complex<type-parameter-0-0>' against 'double'
      conj(const complex<_Tp>& __z)
      ^
  1 error generated.

-- 
mike