title: What are the naming conventions of functions that return boolean?
body: <p>I'm not a native English speaker, so I got confused by the naming convention of functions that return boolean.</p>
  
  <p>I have known the following function names are conventional:</p>
  
  <pre><code>bool is_valid();
  bool is_sorted();
  bool is_empty();
  bool has_children();
  bool can_draw();
  </code></pre>
  
  <p>However, I wonder whether another function names, which begin with verbs other than "is, are, can, has, etc.", are also conventional as follows:</p>
  
  <pre><code>bool TryToCloseWindow();    // check to see if the user tries to close the window
  bool IntendToCloseWindow(); // as above
  bool FileExists();          // check to see if the file exists
  </code></pre>
  
  <p>If you are a native English speaker and programmer, do you think the three function names are conventional?</p>