title: Do the mysql functions open a new mysql connection if the mysql link is not specified?
body: <p>Do functions like mysql_query, mysql_real_escape or mysql_error open a new mysql link if it's not specified ?</p>
  
  <p>php.net says that </p>
  
  <blockquote>
    <p>The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed</p>
  </blockquote>
  
  <p>But what if the connection was made inside a class ? Does php know how to find that link ?</p>
  
  <p>(I'm using the codeigniter framework if that's of any help)</p>