Qt 6.2.2 Webassembly - sign conversion errors

AxelVienna

Hi,
I am trying to port a Qt 6.2.2 C++ application to Webassembly on OpenSuSE Leap 15.3. Compilation as an executable works just fine. When I try to compile with emscripten (version 2.0.14 as requested according to the documentation), I get a lot of signbit and type conversion errors.
It looks to me that the 9er subtree (equivalent to /usr/include/c++/9) is not available in the ...cache/sysroot/include/c++ tree of the emscripten installation. In this path, I find only the v1 subdir which to me looks like the problem.
Thanks for your help and kind regards
Axel

Two examples of error messages below

In file included from ../WhiteEngine/WhiteIncludes.h:14:
In file included from /opt/Qt/6.2.2/wasm_32/include/QtCore/QDateTime:1:
In file included from /opt/Qt/6.2.2/wasm_32/include/QtCore/qdatetime.h:44:
In file included from /opt/Qt/6.2.2/wasm_32/include/QtCore/qstring.h:50:
In file included from /opt/Qt/6.2.2/wasm_32/include/QtCore/qchar.h:43:
In file included from /opt/Qt/6.2.2/wasm_32/include/QtCore/qglobal.h:1430:
In file included from /opt/Qt/6.2.2/wasm_32/include/QtCore/qnumeric.h:44:
/home/mnt/axel/CloudStation/download/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/cmath:317:9: error: no member named 'signbit' in the global namespace; did you mean '__signbit'?
using ::signbit;
      ~~^
/usr/include/bits/mathcalls-helper-functions.h:25:20: note: '__signbit' declared here
__MATHDECL_1 (int, __signbit,, (_Mdouble_ __value))

In file included from ../WhiteEngine/WhiteIncludes.h:6:
In file included from /home/mnt/axel/CloudStation/download/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/iostream:37:
In file included from /home/mnt/axel/CloudStation/download/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/ios:215:
In file included from /home/mnt/axel/CloudStation/download/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/__locale:14:
In file included from /home/mnt/axel/CloudStation/download/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/string:504:
In file included from /home/mnt/axel/CloudStation/download/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/string_view:175:
In file included from /home/mnt/axel/CloudStation/download/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/__string:57:
In file included from /home/mnt/axel/CloudStation/download/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/algorithm:643:
In file included from /home/mnt/axel/CloudStation/download/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/memory:653:
/home/mnt/axel/CloudStation/download/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/typeinfo:221:16: error: reinterpret_cast from 'std::__type_info_implementations::__non_unique_arm_rtti_bit_impl::__type_name_t' (aka 'unsigned int') to 'size_t' (aka 'unsigned long') is not allowed
        return reinterpret_cast<size_t>(__v);

kshegunov

Without having the faintest of clues about the actual problem, at a glance it looks to me like some missing/incomplete/bogus library support issue. I suggest you bring this to the mailing list, we don't get much traffic for wasm here.