On Sun, Jan 13, 2013 at 3:19 PM, Roy Stogner <royst...@ices.utexas.edu> wrote: > > In a tangential aside to a now-closed GitHub ticket, John wrote: > >> std::auto_ptr has actually been deprecated in C++11 >> >> http://en.wikipedia.org/wiki/Auto_ptr >> >> So for that one I'd say let's just wait a few more years and replace >> AutoPtr with std::unique_ptr instead... > > From what I'm reading about C++11, std::unique_ptr could basically be > described as "auto_ptr, but using rvalue references to turn run-time > errors into compile-time errors". So we could probably typedef > unique_ptr as AutoPtr just as soon as we add a --enable-cxx11 option > to configure.
It's actually legal to use unique_ptr's in (move-enabled) versions of standard containers, whereas it's never legal for auto_ptr's. unique_ptr's are also supported in some algorithms (std::sort OK, std::copy NOT OK, http://stackoverflow.com/questions/2876641/so-can-unique-ptr-be-used-safely-in-stl-collections) So it could be tricky to use a typedef: if I'm writing C++11 code and putting "libmesh_typedefd_ptr" into containers, it will compile fine for me but fail for anyone who's running a non-C++11 compliant compiler. > Although I still don't want to require C++11 any time soon, it might > be nice to have as an option, with some macros to enable selective > backwards-compatible enabling of a few features. It appears that > constexpr, move constructors, and rvalue-moving operator overloads, if > used properly, can be easily omitted (or in the constexpr case > replaced with const) to get equivalent C++03 code that's merely less > well optimized. Static asserts can be omitted to get equivalent C++03 > code that's merely less well tested. And method override identifiers > can be omitted to get legal C++03 code that's merely less of either. According to compiler.m4, it looks like we always pass -std=c++0x for GCC 4.4, 4.5, and 4.6, but we don't (that I know of) have any configure tests specifically for the features you mentioned... maybe create a github issue for this to be done? Googling reveals this... http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx_11.html > There doesn't seem to be any way to allow for lambdas, auto, range > loops, or other niceities without breaking C++03 compatibility, which > I'd rather not do for any existing libMesh subsystems. Agreed. Sadly, writing: #ifdef HAVE_CXX11 auto #else crazy<templated<type > >::thing #endif foo = bar(); kind of defeats the purpose... -- John ------------------------------------------------------------------------------ Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS, MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft MVPs and experts. SALE $99.99 this month only -- learn more at: http://p.sf.net/sfu/learnmore_122412 _______________________________________________ Libmesh-devel mailing list Libmesh-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-devel
