Unable to build on Linux: different exception specifier

[codecat]

I'm getting the following compilation failure. Looks like the functions in LibC.h are missing noexcept(true).

This is on gcc 13.2.1 on Fedora.

In file included from /home/nimble/dev/example/thirdparty/sc/Libraries/FileSystem/Internal/FileSystemPosix.inl:11,
                 from /home/nimble/dev/example/thirdparty/sc/Libraries/FileSystem/FileSystem.cpp:12,
                 from /home/nimble/dev/example/thirdparty/sc/SC.cpp:9:
/usr/include/string.h:43:14: error: declaration of ‘void* memcpy(void*, const void*, size_t) noexcept’ has a different exception specifier
   43 | extern void *memcpy (void *__restrict __dest, const void *__restrict __src,
      |              ^~~~~~
In file included from /home/nimble/dev/example/thirdparty/sc/Libraries/Async/Internal/../../File/../Strings/../Strings/../Foundation/Assert.h:6,
                 from /home/nimble/dev/example/thirdparty/sc/Libraries/Async/Internal/../../File/../Strings/../Strings/StringIterator.h:4,
                 from /home/nimble/dev/example/thirdparty/sc/Libraries/Async/Internal/../../File/../Strings/StringView.h:4,
                 from /home/nimble/dev/example/thirdparty/sc/Libraries/Async/Internal/../../File/FileDescriptor.h:7,
                 from /home/nimble/dev/example/thirdparty/sc/Libraries/Async/Internal/../Async.h:12,
                 from /home/nimble/dev/example/thirdparty/sc/Libraries/Async/Internal/AsyncPrivate.h:2,
                 from /home/nimble/dev/example/thirdparty/sc/Libraries/Async/Internal/AsyncLinux.inl:3,
                 from /home/nimble/dev/example/thirdparty/sc/Libraries/Async/Async.cpp:10,
                 from /home/nimble/dev/example/thirdparty/sc/SC.cpp:6:
/home/nimble/dev/example/thirdparty/sc/Libraries/Async/Internal/../../File/../Strings/../Strings/../Foundation/../Foundation/LibC.h:16:11: note: from previous declaration ‘void* memcpy(void*, const void*, SC::size_t)’
   16 |     void* memcpy(void* dst, const void* src, SC::size_t n);
      |           ^~~~~~

[Pagghiu]

yeah, I suspected that the LibC.h would break on some other platforms other than the ones I am actively testing (that is mainly Ubuntu regarding to Linux). I think I got a similar problem with the memchr function that has C++ mangling when including some LibC header from C++ files. As this can grow very complicated soon if you try to handle all possible linux distros, I was thinking to add a "Safety" mode where on unknown platforms I would just include the proper headers from the host toolchain...

I'm wondering if there is a way to know in the header if I am on an ubuntu system vs a Fedora system or other distros 🤔

[codecat]

I just ran into another problem which I assume is related then?

In file included from /home/nimble/dev/example/thirdparty/sc/Libraries/FileSystemIterator/../File/../Foundation/Span.h:4,
                 from /home/nimble/dev/example/thirdparty/sc/Libraries/FileSystemIterator/../File/FileDescriptor.h:5,
                 from /home/nimble/dev/example/thirdparty/sc/Libraries/FileSystemIterator/FileSystemIterator.h:4,
                 from /home/nimble/dev/example/main.cpp:4:
/home/nimble/dev/example/thirdparty/sc/Libraries/FileSystemIterator/../File/../Foundation/../Foundation/InitializerList.h:8:7: error: redefinition of ‘class std::initializer_list<_E>’
    8 | class initializer_list
      |       ^~~~~~~~~~~~~~~~
In file included from /usr/include/c++/13/bits/range_access.h:36,
                 from /usr/include/c++/13/string:53,
                 from /home/nimble/dev/example/build/_deps/hello_imgui-src/src/hello_imgui/../hello_imgui/hello_imgui_assets.h:2,
                 from /home/nimble/dev/example/build/_deps/hello_imgui-src/src/hello_imgui/../hello_imgui/hello_imgui.h:9,
                 from /home/nimble/dev/example/main.cpp:1:
/usr/include/c++/13/initializer_list:45:11: note: previous definition of ‘class std::initializer_list<_E>’
   45 |     class initializer_list
      |           ^~~~~~~~~~~~~~~~

[Pagghiu]

yes that's the same problem, the "safety mode" should also include too.

I will be working on fixing this btw.

[Pagghiu]

Ok I see the issue. If you compile the SC.cpp unity build file with -fno-rtti -fno-exceptions it should work fine.

I think I need to add this to the "how to use / integrate in your project" instructions.

If I can detect whether these flags are on or off I could also probably tackle the required changes automatically

[Pagghiu]

Hi @codecat , I have been also doing some additional fixes.

Now if you pull the latest main branch and compile with exceptions enabled, LibC.h will include instead of trying to use its own forward declarations. As you are using The standard C++ library, you should also define SC_COMPILER_ENABLE_STD_CPP=1 and that should take care of the <initializer_list> issue.

Please let me know if this is fixing your issues.

[codecat]

Looks to be working! Thanks for the fixes! :tada: