testcase for emscripten with async callback

async_callback_test.cpp

#include <iostream>
#include <emscripten.h>

extern "C" {

  void call_async_operation() {

    EM_ASM({AsyncOperation.start()});


    while (!EM_ASM_INT({return AsyncOperation.done})) {
      emscripten_sleep(200);
    }
  }


  // remove throw() => no crash
  static void nothrow_func() throw()
  {
    call_async_operation();

    // remove the following line => no crash
    std::cout << "async operation OK" << std::endl;
  }

  void async_callback_test() {
    nothrow_func();
  }

}

run.sh

mkdir -p out

em++ -Wall -O0 -std=c++0x -fPIC -fPIC -c -o out/async_callback_test.o async_callback_test.cpp

emar rcvs out/libasync_callback_test.a  out/async_callback_test.o

emcc out/libasync_callback_test.a -o out/libasync_callback_test.js \
	-O0 \
	-s EXPORTED_FUNCTIONS="['_async_callback_test']" \
	-s EXTRA_EXPORTED_RUNTIME_METHODS='["ccall"]' \
	-s DISABLE_EXCEPTION_CATCHING=0 \
	-s ALLOW_MEMORY_GROWTH=1 \
	-s EMTERPRETIFY=1 \
	-s EMTERPRETIFY_ASYNC=1 \
	-s ASSERTIONS=2 \
	-s SAFE_HEAP=1 \
	-s DEMANGLE_SUPPORT=1 \
	--profiling-funcs \
	--minify 0 \
	--memory-init-file 0


cat out/libasync_callback_test.js use.js > out/run.js

node out/run.js

use.js

const AsyncOperation = {
    done: false,

    start() {
        // this.done = true; // uncomment this line => no crash
        Promise.resolve().then(() => this.done = true);
    }
};


Module.ccall('async_callback_test', null, [], [], { async: true });