[vtkusers] vtkStdString vs vtkstd::string

[Jeff Baumes]

I wasn't aware of namespace aliasing. If our supported compilers
support it, I'm all for it. But again, we have to do some testing
first to see how using std:: goes before we make that switch.

Jeff

On Thu, Jan 14, 2010 at 9:59 AM, Marcus D. Hanwell
<marcus.hanwell at kitware.com> wrote:
> I am with Francois, can we use namespace aliasing? I think with the work I
> have been doing (when I have had time) on GCC default visibility in VTK
> keeping the symbols short should be much less of an issue with supported
> compilers too. Initial indications are a 30-40% drop in exported symbols in
> most kits.
>
> Marcus
>
> On Thursday 14 January 2010 09:24:44 Francois Bertel wrote:
>> As a macro hater, can I suggest "namespace aliasing" instead?
>>
>> Here is what I mean with a full example (just tested with gcc 4.4.1)
>>
>> #include <iostream>
>>
>> int main()
>> {
>>   // define vtkstd as an alias to std
>>   namespace vtkstd=std;
>>
>>   vtkstd::cout << "hello" << vtkstd::endl;
>>
>>   return 0;
>> }
>>
>> On Thu, Jan 14, 2010 at 9:09 AM, Jeff Baumes <jeff.baumes at kitware.com>
> wrote:
>> > On Wed, Jan 13, 2010 at 7:15 PM, David Doria <daviddoria+vtk at gmail.com>
> wrote:
>> >> The doc for vtkStdString says:
>> >>
>> >> Wrapper around vtkstd::string to keep symbols short.
>> >> vtkStdString derives from vtkstd::string to provide shorter symbol
>> >> names than basic_string<...> in namespace std given by the standard
>> >> STL string.
>> >>
>> >> But I guess I don't understand what that means. When should one use
>> >> vtkStdString vs vtkstd::string?
>> >
>> > I don't know the answer to your question, but it would be nice if all
>> > these pointed to the same underlying thing: std::string. I'm assuming
>> > the older compilers are responsible for the need for short symbols.
>> > Perhaps the compiler deprecation that Berk sent recently will allow us
>> > to eventually replace all vtkStdString and vtkstd::string with
>> > std::string?
>> >
>> > We are thinking to maybe start testing the use of std::string in the
>> > examples first.
>> >
>> > Longer term, we could do something like the following:
>> >
>> > typedef std::string vtkStdString;
>> > #define vtkstd std
>> >
>> > So the old type names could still be used, but we could in time
>> > replace all occurrences in VTK to just use std::string. Eventually the
>> > old aliases could be removed.
>> >
>> > But there could be unforeseen issues with this idea that force us to
>> > continue using vtkStdString/vtkstd::string.
>> >
>> > Jeff
>> > _______________________________________________
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>
> --
> Marcus D. Hanwell, Ph.D.
> R&D Engineer, Kitware Inc.
> (518) 881-4937
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