[vtk-developers] Errors when compiling VTK v6.0.0 in C++11 mode

[David Gobbi]

Hi Robert,

I can hardly assume that std::isinf is a template, on some systems it
is simply an overloaded function.  A try_compile is a messier solution
than I'm hoping for, but I've already developed a nice, compact check
and am refining it with some advice from Brad.

 - David

On Tue, Jul 16, 2013 at 9:19 AM, Robert Maynard
<robert.maynard at kitware.com> wrote:
> The problem actually is that CHECK_CXX_SYMBOL_EXISTS doesn't support
> templated functions.
> If you look at the CMakeError.log you will see that the
> check_cxx_symbol_exists tries to determine
> if the function ((int*)(&std::isinf))[argc]; is valid. This won't work
> for templated functions instead you
> need to check for ((int*)(&std::isinf<int>))[argc];
>
> I don't know if VTK should extend CheckCXXSymbolExists to state that
> they are looking for a templated
> function, or just write a custom try_compile.
>
>
> On Tue, Jul 16, 2013 at 10:21 AM, David Gobbi <david.gobbi at gmail.com> wrote:
>> Hi Robert,
>>
>> I tried.  Turns out that CHECK_CXX_SYMBOL_EXISTS is only for
>> preprocessor symbols or symbols with C linkage, the only difference
>> from CHECK_SYMBOL_EXISTS is that it does these checks with a C++
>> compiler.  It will always return false when used to check for
>> std::isnan.
>>
>> - David
>>
>> On Tue, Jul 16, 2013 at 7:42 AM, Robert Maynard
>> <robert.maynard at kitware.com> wrote:
>>> If you need to use the c++ compiler to verify that symbols exist
>>> inside a namespace, you should use CHECK_CXX_SYMBOL_EXISTS.
>>>
>>> On Sat, Jul 13, 2013 at 1:21 PM, David Gobbi <david.gobbi at gmail.com> wrote:
>>>> Hi Kevin,
>>>>
>>>> Thanks for the report.  I believe that this can be fixed.  The patch
>>>> that Kyle provided will not work (we already tried that in earlier
>>>> rounds of testing) so now I am investigating in more depth. I've
>>>> discovered that our cmake check for VTK_HAS_STD_ISINF doesn't work
>>>> because cmake's check_symbol_exists() function uses the C compiler,
>>>> rather than the C++ compiler, for its try_compile and therefore
>>>> doesn't work with namespaced functions.  I hope to have a patch up on
>>>> gerrit soon.
>>>>
>>>>  - David
>>>>
>>>> On Sat, Jul 13, 2013 at 4:51 AM, Sean McBride <sean at rogue-research.com> wrote:
>>>>> On Wed, 10 Jul 2013 16:31:47 +0200, Kevin Funk said:
>>>>>
>>>>>>/home/krf/devel/src/VTK-master/Common/Core/vtkMath.h: In static member
>>>>>>function 'static int vtkMath::IsInf(double)':
>>>>>>/home/krf/devel/src/VTK-master/Common/Core/vtkMath.h:1249:18: error: call of
>>>>>>overloaded 'isinf(double&)' is ambiguous
>>>>>>
>>>>>> *SNIP*
>>>>>>
>>>>>>Since there are C++11 checks all over the code base I'd assume one can
>>>>>>compile
>>>>>>VTK in C++11 mode.
>>>>>
>>>>> With which compiler, standard library, and OS do you see this?
>>>>>
>>>>> My Rogue7 dashboard builds as C++11 nightly with clang on OS X, and this doesn't happen there.
>>>>>
>>>>> The patch looks reasonable, but this code is fragile, it took David Gobbi and I a while to get it working with all (mmmm, most!) compiler/library/OS/language combinations.
>>>>>
>>>>> I'm away on vacation, and have no VTK or compiler to look at this until next week, but maybe David can...
>>>>>
>>>>> Cheers,
>>>>>
>>>>> --
>>>>> ____________________________________________________________
>>>>> Sean McBride, B. Eng                 sean at rogue-research.com
>>>>> Rogue Research                        www.rogue-research.com
>>>>> Mac Software Developer              Montréal, Québec, Canada
>>>>>
>>>>>
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