How do we call a function with parameters and use output returning true/false in php?

[bakertaylor28]

How do we use something like the following? I can't seem to find anything practical on how to use the true/false return or on how to supply parameters to a function.

<?php

function validate_email($email){

   $exp = "^[a-z\'0-9]+([._-][a-z\'0-9]+)*@([a-z0-9]+([._-][a-z0-9]+))+$";

   if(eregi($exp,$email)){

      if(checkdnsrr(array_pop(explode("@",$email)),"MX")){
        return true;
      }else{
        return false;
      }

   }else{

      return false;

   }    
}

?>