How to link the static library when compile C/C++ file to wasm?

[Arion Wong]

I am working on windows 10. And I want to compile a C++ file  to wasm. This C++ code call function from a static library.

I compile the file with this command line :emcc cppfile.cpp -Os -s WASM=1 -s SIDE_MODULE=1 -o cppfile.wasm -s RUNTIME_LINKED_LIBS=['library.lib']  -I "F:/wzm/MonoProject/include"

I load the wasm file with this code :

function loadWebAssembly(filename, imports = {}) {
  return fetch(filename)
    .then(response => response.arrayBuffer())
    .then(buffer => WebAssembly.compile(buffer))
    .then(module => {
      imports.env = imports.env || {}
      Object.assign(imports.env, {
        memoryBase: 0,
        tableBase: 0,
        memory: new WebAssembly.Memory({ initial: 256, maximum: 256 }),
        table: new WebAssembly.Table({ initial: 0, maximum: 0, element: 'anyfunc' })
      })
      return new WebAssembly.Instance(module, imports)
    })
}

But when I load the wasm file , the console return me a error:

Uncaught (in promise) LinkError: WebAssembly Instantiation: Import #1 module="env" function="_mono_class_get_method_from_name" error: function import requires a callable

    at fetch.then.then.then.module (http://localhost:8000/loader.js:13:14)

    at <anonymous>

It mean I don't link the library.

How to link the static library?

[Alon Zakai]

That error means it expects a function to be provided for that import, so your exports object must contain a property "env", and on that object, a property "_mono_class_get_method_from_name".

How are you generating the imports?

Based on the name of the missing import, I'm guessing you may need all of mono - the easiest thing is to build it normally with emscripten and let emscripten do the loading of the library for you. However, if your library just needs a tiny subset of the functionality, perhaps you can implement it directly somehow. I'd take a look at the list of imports for the wasm module to see.

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