trying to run function just once

This should work for you, not tested.

PHP Code:

protected static $runOnce = true;

if ($runOnce === true)
{
    // run your code
}
else
{
    static::$runOnce = false;
} 


What did you Try? What did you Get? What did you Expect?

Joined CodeIgniter Community 2009.  ( Skype: insitfx )