title: Open file in C++ using int as a mode
body: <p>I ran into this code for opening file and I'm trying to understand if this line also creates a file if it doesn't exist. But I have never seen this and couldn't find it.</p>
  
  <pre><code>int ret = ::open(filename, 0200);
  </code></pre>
  
  <p>Can someone explain the '::' and the '0200'? 
  Is this form acceptable/reasonable to use?</p>
  
  <p>Thanks</p>
  
  <p>Edit: I use linux x86 platform</p>