[vtk-developers] Introducing (optional) C++11 features in VTK
Moreland, Kenneth
kmorel at sandia.gov
Mon Aug 18 18:25:53 EDT 2014
+1 for me too.
However, my vote is actually to introduce things like VTK_OVERRIDE and VTK_FINAL until pre-C++11 compilers get abandoned. I find it disconcerting when libraries try to get cute with changing the behavior of (or trying to emulate) keywords with preprocessor macros. It can be pretty confusing when something goes wrong, and good luck if you have to use two separate projects together that both tried to define preprocessor macros with different implementations.
-Ken
From: Andrew Maclean <andrew.amaclean at gmail.com<mailto:andrew.amaclean at gmail.com>>
Reply-To: "andrew.amaclean at gmail.com<mailto:andrew.amaclean at gmail.com>" <andrew.amaclean at gmail.com<mailto:andrew.amaclean at gmail.com>>
Date: Monday, August 18, 2014 4:09 PM
To: VTK Developers <vtk-developers at vtk.org<mailto:vtk-developers at vtk.org>>, "Marcus D. Hanwell" <marcus.hanwell at kitware.com<mailto:marcus.hanwell at kitware.com>>, Ben Boeckel <ben.boeckel at kitware.com<mailto:ben.boeckel at kitware.com>>, Sean McBride <sean at rogue-research.com<mailto:sean at rogue-research.com>>
Subject: [EXTERNAL] Re: [vtk-developers] Introducing (optional) C++11 features in VTK
+1! ... actually: ++1 :-)
I would support this. To keep VTK relevant we need to be introducing these features. Especially features like nullptr, unique_ptr etc.
But I would not be happy at introducing more VTK defines like VTK_OVERRIDE and VTK_FINAL - unless absolutely necessary. I much prefer Sean's idea of using a modernise tool.
Regards
Andrew
On Tue, Aug 19, 2014 at 7:05 AM, <vtk-developers-request at vtk.org<mailto:vtk-developers-request at vtk.org>> wrote:
---------- Forwarded message ----------
From: "Marcus D. Hanwell" <marcus.hanwell at kitware.com<mailto:marcus.hanwell at kitware.com>>
To: VTK Developers <vtk-developers at vtk.org<mailto:vtk-developers at vtk.org>>
Cc:
Date: Mon, 18 Aug 2014 13:45:37 -0400
Subject: [vtk-developers] Introducing (optional) C++11 features in VTK
Hi,
As we move forward, it would be great to get a feeling for people's
thoughts about integrating some components of C++11 optionally. So if
C++11 is available/enabled, there are several features we could enable
optionally at compile time.
A very simple example is that of the new override keyword, that is
used to indicate that a member function is overriding a virtual
function. Using this can avoid mistakes where the signature changes
and derived classes are missed. It can be defined in a header (empty
on old compilers, override with recent compilers). Final is similar,
indicating that the virtual function cannot be overridden in derived
classes.
This would introduce changes to the VTK coding style, where we now use
virtual for all virtual functions (first declaration, or subsequent
overrides). We could introduce this gradually for new code, even
having one or two dashboards compiling this way would help spot simple
errors such as an incorrect signature not actually overriding a
function, but in fact declaring a new virtual for example.
In these cases I would suggest simple naming, so VTK_OVERRIDE and
VTK_FINAL would be used where a C++11 only code would simply use the
new keywords.
Thoughts, objections? There are lots of other features, and I know it
will be a while before we can use them all but it would be great to
make a start with some of the easier ones that can improve code
quality with little overhead.
Marcus
---------- Forwarded message ----------
From: Ben Boeckel <ben.boeckel at kitware.com<mailto:ben.boeckel at kitware.com>>
To: "Marcus D. Hanwell" <marcus.hanwell at kitware.com<mailto:marcus.hanwell at kitware.com>>
Cc: VTK Developers <vtk-developers at vtk.org<mailto:vtk-developers at vtk.org>>
Date: Mon, 18 Aug 2014 14:21:56 -0400
Subject: Re: [vtk-developers] Introducing (optional) C++11 features in VTK
On Mon, Aug 18, 2014 at 13:45:37 -0400, Marcus D. Hanwell wrote:
> Thoughts, objections? There are lots of other features, and I know it
> will be a while before we can use them all but it would be great to
> make a start with some of the easier ones that can improve code
> quality with little overhead.
What about "= delete" for removing default assignment and copy
constructors?
--Ben
---------- Forwarded message ----------
From: "Marcus D. Hanwell" <marcus.hanwell at kitware.com<mailto:marcus.hanwell at kitware.com>>
To: Ben Boeckel <ben.boeckel at kitware.com<mailto:ben.boeckel at kitware.com>>
Cc: VTK Developers <vtk-developers at vtk.org<mailto:vtk-developers at vtk.org>>
Date: Mon, 18 Aug 2014 14:29:10 -0400
Subject: Re: [vtk-developers] Introducing (optional) C++11 features in VTK
On Mon, Aug 18, 2014 at 2:21 PM, Ben Boeckel <ben.boeckel at kitware.com<mailto:ben.boeckel at kitware.com>> wrote:
> On Mon, Aug 18, 2014 at 13:45:37 -0400, Marcus D. Hanwell wrote:
>> Thoughts, objections? There are lots of other features, and I know it
>> will be a while before we can use them all but it would be great to
>> make a start with some of the easier ones that can improve code
>> quality with little overhead.
>
> What about "= delete" for removing default assignment and copy
> constructors?
>
Certainly, I think we should start out simple and then build it out.
If we have prototypes for a few of the most useful features that can
easily be encapsulated in compile time logic that will degrade to
C++98 that would be great.
Marcus
---------- Forwarded message ----------
From: "Sean McBride" <sean at rogue-research.com<mailto:sean at rogue-research.com>>
To: "Marcus D. Hanwell" <marcus.hanwell at kitware.com<mailto:marcus.hanwell at kitware.com>>, "VTK Developers" <vtk-developers at vtk.org<mailto:vtk-developers at vtk.org>>
Cc:
Date: Mon, 18 Aug 2014 16:50:12 -0400
Subject: Re: [vtk-developers] Introducing (optional) C++11 features in VTK
On Mon, 18 Aug 2014 13:45:37 -0400, Marcus D. Hanwell said:
>As we move forward, it would be great to get a feeling for people's
>thoughts about integrating some components of C++11 optionally. So if
>C++11 is available/enabled, there are several features we could enable
>optionally at compile time.
+1 from me.
nullptr is another one that can be made to work even on older compilers with some #define glue.
Instead of creating a 'VTK_OVERRIDE', we could also use 'override' as if we required C++11 and "#define override /* nothing */" as appropriate. Then when C++11 really is the minimun requirement no big find/replace is required. Just a thought.
PS: I already have dashboards building as C++11 and C++14.
Cheers,
--
____________________________________________________________
Sean McBride, B. Eng sean at rogue-research.com<mailto:sean at rogue-research.com>
Rogue Research www.rogue-research.com<http://www.rogue-research.com>
Mac Software Developer Montréal, Québec, Canada
---------- Forwarded message ----------
From: "Sean McBride" <sean at rogue-research.com<mailto:sean at rogue-research.com>>
To: "Marcus D. Hanwell" <marcus.hanwell at kitware.com<mailto:marcus.hanwell at kitware.com>>, "VTK Developers" <vtk-developers at vtk.org<mailto:vtk-developers at vtk.org>>
Cc:
Date: Mon, 18 Aug 2014 17:05:38 -0400
Subject: Re: [vtk-developers] Introducing (optional) C++11 features in VTK
On Mon, 18 Aug 2014 16:50:12 -0400, Sean McBride said:
>nullptr is another one that can be made to work even on older compilers
>with some #define glue.
>
>Instead of creating a 'VTK_OVERRIDE', we could also use 'override' as if
>we required C++11 and "#define override /* nothing */" as appropriate.
>Then when C++11 really is the minimun requirement no big find/replace is
>required. Just a thought.
I hit send too fast...
I also wanted to suggest looking at the clang-modernize tool, which is "a standalone tool used to automatically convert C++ code written against old standards to use features of the newest C++ standard".
<http://clang.llvm.org/extra/clang-modernize.html>
Specifically, it can be used to automatically add 'override' and convert to 'nullptr':
<http://clang.llvm.org/extra/AddOverrideTransform.html>
<http://clang.llvm.org/extra/UseNullptrTransform.html>
Cheers,
--
____________________________________________________________
Sean McBride, B. Eng sean at rogue-research.com<mailto:sean at rogue-research.com>
Rogue Research www.rogue-research.com<http://www.rogue-research.com>
Mac Software Developer Montréal, Québec, Canada
--
___________________________________________
Andrew J. P. Maclean
___________________________________________
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