fix compile errors when using gcc and clang

[doug-moen]

When compiling using gcc or clang, Volumes.h produced 8 compile errors like this:

./Volumes.h:134:10: error: explicit specialization of 'surface' in class scope
                double surface<Surface::Sphere>(const double x, const double y, const double z)
                       ^

The problem is that the C++ standard does not permit a template to be specialized in class scope, only in namespace scope, but Microsoft Visual C++ allows this as a language extension, and gcc/clang do not.
Reference: https://stackoverflow.com/questions/3052579/explicit-specialization-in-non-namespace-scope

The fix is to move the template specializations out of the Volumes::Surface class and define them in namespace scope.

[rogrosso]

Dear Doug, I have the Ubuntu 20.04 LTS in Windows 10 and used the clang compiler 10.0.0-4. I compiled the code with clang++ -o dmc -std=c++17 *.cpp This command line does not produce any error. The code compiles and run. The code was developed using Visual Studio 2019 community. I set the compiler option `C++ Language Standard` to `ISO C++ 17 Standard`. In the Ubuntu terminal I also run the compiler with the option -std=c++11. I think, it will require a bunch of work to compile the code with this standard. If it is required, I can tray to fix the syntax. Remember that the code was developed for research and at the moment these are all the compilers I can use for testing. But I like the idea of someone intending to use the software. As soon as I have time I will start fixing the problems with the Volumes class. But I am afraid, we have much more work than just fixing the template specialization issue. Sincerely R.Grosso Von: Doug Moen <notifications@github.com> Gesendet: Sunday, August 2, 2020 1:49 AM An: rogrosso/tmc <tmc@noreply.github.com> Cc: Subscribed <subscribed@noreply.github.com> Betreff: [rogrosso/tmc] fix compile errors when using gcc and clang (#3) When compiling using gcc or clang, Volumes.h produced 8 compile errors like this: ./Volumes.h:134:10: error: explicit specialization of 'surface' in class scope double surface<Surface::Sphere>(const double x, const double y, const double z) ^ The problem is that the C++ standard does not permit a template to be specialized in class scope, only in namespace scope, but Microsoft Visual C++ allows this as a language extension, and gcc/clang do not. Reference: https://stackoverflow.com/questions/3052579/explicit-specialization-in-non-namespace-scope The fix is to move the template specializations out of the Volumes::Surface class and define them in namespace scope.

…

_____ You can view, comment on, or merge this pull request online at: #3 Commit Summary * fix compile errors when using gcc and clang File Changes * M cpp_dmc/Volumes.h <https://github.com/rogrosso/tmc/pull/3/files#diff-3b16aab62dc52fb548bfed8cab510514> (164) Patch Links: * https://github.com/rogrosso/tmc/pull/3.patch * https://github.com/rogrosso/tmc/pull/3.diff — You are receiving this because you are subscribed to this thread. Reply to this email directly, <#3> view it on GitHub, or <https://github.com/notifications/unsubscribe-auth/AEW4WUHP6LLIVQFBDIBWBTDR6SSV5ANCNFSM4PSEVLRQ> unsubscribe.

[ChristopherFowler]

When compiling using gcc or clang, Volumes.h produced 8 compile errors like this:

./Volumes.h:134:10: error: explicit specialization of 'surface' in class scope
                double surface<Surface::Sphere>(const double x, const double y, const double z)
                       ^

The problem is that the C++ standard does not permit a template to be specialized in class scope, only in namespace scope, but Microsoft Visual C++ allows this as a language extension, and gcc/clang do not. Reference: https://stackoverflow.com/questions/3052579/explicit-specialization-in-non-namespace-scope

The fix is to move the template specializations out of the Volumes::Surface class and define them in namespace scope.

For what it is worth, I'm going to fix this issue and make it work because I would like to use your code.