How can i handle my own try catch?

[eluser]Sarwar CSE[/eluser]
I want like this

Code:

function Test(){
             try {
   msgon . open ();
  } catch ( Exception $ex ) {
   echo "Here i want to to show msgon is undifine but it goes to CI";
  }
}

if i wrote a try catch block then if error occurs then it will handle my catch block i don't want to handle it by CI handler .

How can i do this?

please advice me?

[eluser]InsiteFX[/eluser]
Extend the ./system/core/Exceptions.php Class.