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blazor-webassemblywebassemblyemscripten

Multiple errors while building WebAssembly project

I am trying to build simple webassembly app that consumes a JS object reference (of type emscripten::val or emscripten::EM_VAL).

The code:

#include <emscripten.h>
#include <emscripten/bind.h>
#include <emscripten/val.h>

extern "C"
{
    EMSCRIPTEN_KEEPALIVE void Draw(emscripten::val canvas)
    {
        emscripten::val::global("console").call<void>("log", canvas);
    }
}

I have tried to build the project that consists only of the code above using emcc (installed according to instruction), Emscripten CMake toolchain and Blazor WebAssembly (C#/.NET, instruction). Regardless of the way the C++ code is being attempted to compile to wasm, I see the same multiple errors in the output:

NativeClient_0.o: undefined symbol: _emval_get_global
NativeClient_0.o: undefined symbol: _emval_decref
NativeClient_0.o: undefined symbol: _emval_call_void_method
NativeClient_0.o: undefined symbol: _emval_get_method_caller
NativeClient_0.o: undefined symbol: _emval_incref

There are some related issues on github (1, 2). Apart from that I was unable to find any related info and couldn't get my code compiled. What am I doing wrong?

Solution

  • Use --bind for emcc and em++ compilers and remove -s WASM=1 if using it.