title: PHP reuse: What are the differences between "include files" and "functions"?
body: <p>What are the differences between "include files" and "functions" for reusing code in PHP?</p>
  
  <p>I can enumerate 1 difference: when using a function, the caller script don't have access to the function local vars but when including the includer script has access to the local vars of the included script.</p>
  
  <p>What are other differences?</p>
  
  <p>When should i use "functions" and when should i use "include files"?</p>
  
  <p>For DB connection which one is usually used?</p>