title: Is PHP function names case-sensitive or not?
body: <p>I am from Java background. 
  In Java, every method has case-sensitive while calling. But in PHP, I didn't see the case-sensitive function name while calling the functions.</p>
  
  <pre><code>class Sample {
  
      ...
      ...
  
      function sampleFunction() {
  
         ....
         ....
  
      }
  
  }
  
  $obj = new Sample();
  $obj-&gt;sampleFunction(); /* Proper call with function name */
  $obj-&gt;samplefunction(); /* It should show undefined function error but it also calls sampleFunction()  */
  </code></pre>
  
  <p>Can anyone clear my doubt why this is also called even non-case sensitive function name. And please give me how to restrict in PHP?</p>
  
  <p>Thanks in advance.</p>