Function run

example/callback.cc:58–138

void run() {
  // Initialize.
  std::cout << "Initializing..." << std::endl;
  auto engine = wasm::Engine::make();
  auto store_ = wasm::Store::make(engine.get());
  auto store = store_.get();

  // Load binary.
  std::cout << "Loading binary..." << std::endl;
  std::ifstream file("callback.wasm");
  file.seekg(0, std::ios_base::end);
  auto file_size = file.tellg();
  file.seekg(0);
  auto binary = wasm::vec<byte_t>::make_uninitialized(file_size);
  file.read(binary.get(), file_size);
  file.close();
  if (file.fail()) {
    std::cout << "> Error loading module!" << std::endl;
    exit(1);
  }

  // Compile.
  std::cout << "Compiling module..." << std::endl;
  auto module = wasm::Module::make(store, binary);
  if (!module) {
    std::cout << "> Error compiling module!" << std::endl;
    exit(1);
  }

  // Create external print functions.
  std::cout << "Creating callback..." << std::endl;
  auto print_type = wasm::FuncType::make(
    wasm::ownvec<wasm::ValType>::make(wasm::ValType::make(wasm::ValKind::I32)),
    wasm::ownvec<wasm::ValType>::make(wasm::ValType::make(wasm::ValKind::I32))
  );
  auto print_func = wasm::Func::make(store, print_type.get(), print_callback);

  // Creating closure.
  std::cout << "Creating closure..." << std::endl;
  int i = 42;
  auto closure_type = wasm::FuncType::make(
    wasm::ownvec<wasm::ValType>::make(),
    wasm::ownvec<wasm::ValType>::make(wasm::ValType::make(wasm::ValKind::I32))
  );
  auto closure_func = wasm::Func::make(store, closure_type.get(), closure_callback, &i);

  // Instantiate.
  std::cout << "Instantiating module..." << std::endl;
  auto imports = wasm::vec<wasm::Extern*>::make(
    print_func.get(), closure_func.get());
  auto instance = wasm::Instance::make(store, module.get(), imports);
  if (!instance) {
    std::cout << "> Error instantiating module!" << std::endl;
    exit(1);
  }

  // Extract export.
  std::cout << "Extracting export..." << std::endl;