binji · March 28, 2020 01:35
diff --git a/commandline b/commandline
 emcc test.c -o test.js -s EXPORTED_FUNCTIONS='["_get", "_increment"]'
diff --git a/test.c b/test.c
 int my_var = 42;

 int* get(void) { return &my_var; }

 void increment(void) { my_var++; }
diff --git a/test.html b/test.html
 <!doctype html>
 <script src="test.js"></script>
 <p>my_var: ???</p>
 <button>increment</button>
 <script>
  let p = document.querySelector('p');
  let button = document.querySelector('button');

  // Click the button to increment the variable. <p> won't be updated immediately.
  button.addEventListener('click', () => { _increment(); });

  // Wait for emscripten to initialize the module.
  addOnInit(() => {
    // Read the address of my_var.
    let addr = _get();

    // Every half second...
    setInterval(() => {
      // Read the value of my_var from memory.
      let value = HEAP32[addr>>2];
      // Update the <p> element.
      p.textContent = `my_var: ${value}`;
    }, 500);
  });
 </script>
	<!doctype html>
	<script src="test.js"></script>
	<p>my_var: ???</p>
	<button>increment</button>
	<script>
	let p = document.querySelector('p');
	let button = document.querySelector('button');

	// Click the button to increment the variable. <p> won't be updated immediately.
	button.addEventListener('click', () => { _increment(); });

	// Wait for emscripten to initialize the module.
	addOnInit(() => {
	// Read the address of my_var.
	let addr = _get();

	// Every half second...
	setInterval(() => {
	// Read the value of my_var from memory.
	let value = HEAP32[addr>>2];
	// Update the <p> element.
	p.textContent = `my_var: ${value}`;
	}, 500);
	});
	</script>