How to find what roles user has in Drupal

User object in Drupal has a roles array and all you have to do is to check if this array has the role you want.

Here is an example:

<?php
  global $user;
  $user->roles[ "ROLE_ID" ] = "ROLE_NAME";

  // You can traverse through the array
  // and check if user has the role you want
  foreach($user->roles as $rid => $role){
    if($role == "role_i_want"){
      // Do something
    }
  }
?>