[vtk-developers] Introducing (optional) C++11 features in VTK

Wed Aug 20 17:24:50 EDT 2014

+1


On Tue, Aug 19, 2014 at 11:16 AM, Marcus D. Hanwell <
marcus.hanwell at kitware.com> wrote:

> Yes, and there are more extensive examples in the Qt project (for 5+),
> and Boost where they both used the prefixed macro name approach. I can
> get some of the basics in pretty quickly as I haven't heard much
> opposition.
>
> Marcus
>
> On Mon, Aug 18, 2014 at 10:28 PM, Andrew Maclean
> <andrew.amaclean at gmail.com> wrote:
> > Brilliant! It looks as if ITK has already done a lot of this!
> >
> >
> > Andrew
> >
> >
> >
> > On Tue, Aug 19, 2014 at 10:19 AM, Matt McCormick
> > <matt.mccormick at kitware.com> wrote:
> >>
> >> VTK_OVERRIDE would be nice, and it would be nice to macros that are
> >> similar to ITK.  Currently there is
> >>
> >>   ITK_OVERRIDE
> >>   ITK_NOEXCEPT
> >>   ITK_NULLPTR
> >>
> >>
> >>
> http://itk.org/gitweb?p=ITK.git;a=blob;f=Modules/Core/Common/include/itkMacro.h;h=aa4d40d7f5042eaf3c696af469d4cf0848239935;hb=HEAD#l121
> >>
> >>
> >> Thanks,
> >> Matt
> >>
> >> On Mon, Aug 18, 2014 at 7:25 PM, Marcus D. Hanwell
> >> <marcus.hanwell at kitware.com> wrote:
> >> > I am with David Gobbi and Ken. It would be a simple search and replace
> >> > once support for pre-C++11 compilers were dropped and the potential
> >> > for unintended consequences is too great. Glad to see there is general
> >> > support, I should have included more on my reasoning, but didn't want
> >> > to go into too much detail on implementation if there was little
> >> > support for it.
> >> >
> >> > It sounds like there is, nullptr is definitely another piece of low
> >> > hanging fruit. There is lots more that would be great to use, the
> >> > language is evolving and it is important that we take advantage of the
> >> > parts that make sense.
> >> >
> >> > Marcus
> >> >
> >> > On Mon, Aug 18, 2014 at 6:43 PM, David Gobbi <david.gobbi at gmail.com>
> >> > wrote:
> >> >> Yes, I also believe that using "#define override" has the potential
> to
> >> >> cause problems.  Let's say that "override" appears as a variable
> >> >> somewhere in code that someone brought into VTK and tested with a
> >> >> C++11 compiler (this is legal, since "override" is not a keyword).
> >> >> Then someone else tries compiling that code on C++03 where the
> >> >> "#define override" is active.  All of a sudden, "override" is
> replaced
> >> >> by nothing anywhere it is used as a variable (or as any other kind of
> >> >> identifier).
> >> >>
> >> >>
> >> >> On Mon, Aug 18, 2014 at 4:29 PM, Andrew Maclean
> >> >> <andrew.amaclean at gmail.com> wrote:
> >> >>> Hi Ken
> >> >>>
> >> >>> Good point, thanks for that.
> >> >>>
> >> >>> Andrew
> >> >>>
> >> >>>
> >> >>> On Tue, Aug 19, 2014 at 8:25 AM, Moreland, Kenneth <
> kmorel at sandia.gov>
> >> >>> wrote:
> >> >>>>
> >> >>>> +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>
> >> >>>> Reply-To: "andrew.amaclean at gmail.com" <andrew.amaclean at gmail.com>
> >> >>>> Date: Monday, August 18, 2014 4:09 PM
> >> >>>> To: VTK Developers <vtk-developers at vtk.org>, "Marcus D. Hanwell"
> >> >>>> <marcus.hanwell at kitware.com>, Ben Boeckel <ben.boeckel at kitware.com
> >,
> >> >>>> Sean
> >> >>>> McBride <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>
> >> >>>> wrote:
> >> >>>>>
> >> >>>>>
> >> >>>>> ---------- Forwarded message ----------
> >> >>>>> From: "Marcus D. Hanwell" <marcus.hanwell at kitware.com>
> >> >>>>> To: VTK Developers <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>
> >> >>>>> To: "Marcus D. Hanwell" <marcus.hanwell at kitware.com>
> >> >>>>> Cc: VTK Developers <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>
> >> >>>>> To: Ben Boeckel <ben.boeckel at kitware.com>
> >> >>>>> Cc: VTK Developers <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>
> >> >>>>> 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>
> >> >>>>> To: "Marcus D. Hanwell" <marcus.hanwell at kitware.com>, "VTK
> >> >>>>> Developers"
> >> >>>>> <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
> >> >>>>> Rogue Research                        www.rogue-research.com
> >> >>>>> Mac Software Developer              Montréal, Québec, Canada
> >> >>>>>
> >> >>>>>
> >> >>>>>
> >> >>>>>
> >> >>>>>
> >> >>>>> ---------- Forwarded message ----------
> >> >>>>> From: "Sean McBride" <sean at rogue-research.com>
> >> >>>>> To: "Marcus D. Hanwell" <marcus.hanwell at kitware.com>, "VTK
> >> >>>>> Developers"
> >> >>>>> <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,
> >> >> _______________________________________________
> >> >> Powered by www.kitware.com
> >> >>
> >> >> Visit other Kitware open-source projects at
> >> >> http://www.kitware.com/opensource/opensource.html
> >> >>
> >> >> Follow this link to subscribe/unsubscribe:
> >> >> http://public.kitware.com/mailman/listinfo/vtk-developers
> >> >>
> >> > _______________________________________________
> >> > Powered by www.kitware.com
> >> >
> >> > Visit other Kitware open-source projects at
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> >> >
> >> > Follow this link to subscribe/unsubscribe:
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> >> >
> >
> >
> >
> >
> > --
> > ___________________________________________
> > Andrew J. P. Maclean
> >
> > ___________________________________________
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
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