title: What does the |= Operator mean?
body: <p>In some code i found this <code>|=</code> operator used to return a <code>uint</code> but i can find something about it on the internet and i wanna understand how it works and what are the return values in this case.</p>
  
  <pre><code>public uint Mask
  {
      get
      {
          uint num = 0;
          if (_0)
              num |= 1U;
          if (_1)
              num |= 2U;
          if (_2)
              num |= 4U;
          return num;
      }
  }
  </code></pre>
  
  <p>a detailed answer will be much appreciated.</p>