C#

Daniel Grunwald wrote:

What your code is doing is:
- read a
- read b
- perform the comparison

Any other thread may write between those two reads. Being "atomic" doesn't apply to the comparison as it only deals with local values.

Daniel Grunwald wrote:

There is no Interlocked.ReferenceEquals, you're just calling the inherited Object.ReferenceEquals.

Daniel Grunwald wrote:

AFAIK there is no way to read two references atomically (so that no other thread can write between the two reads).

lock(myLock) {
    if (a==b) doSomething();
}

void Button_OnClick(object sender, eventargs args)
{
  //......
}

void Button_OnClick(object sender, eventargs args)
{
  Button buttonClicked = sender as Button;
  if(buttonClicked == null)
    return;
  string buttonText = buttonClicked.Text;
  // use buttonText here or wherever....
}

private void ButtonEventHandler(object sender, EventArgs e)
{
  Button button = sender as Button;
  if (button == null) return;
  txtClicked.Text = button.Text;
}