使用joomla插件文件中的函数

As stated in my question, how can i use the function which is inside joomla plugin folder from an external php file?

To be exact, it is under this patch "/plugins/system/rsfppayment/rsfppayment.php" and I want to use the function rsfp_afterConfirmPayment(). I pasted the code snippet below and this file is from rsForm Pro Paypal payment plugin.

// no direct access
defined( '_JEXEC' ) or die( 'Restricted access' );

/**
 * RSForm! Pro Payment Plugin
 */
class plgSystemRSFPPayment extends JPlugin
{
function rsfp_afterConfirmPayment($SubmissionId) {
        RSFormProHelper::sendSubmissionEmails($SubmissionId);
    }
}

You can do the following:

require_once('/plugins/system/rsfppayment/rsfppayment.php');
$objplgSystemRSFPPayment = new plgSystemRSFPPayment();
$objplgSystemRSFPPayment->rsfp_afterConfirmPayment($submissionId);

Of course, you need to make sure that the path is correct and the value of $submissionId is valid.

Post the complete code then you use. The code of itoctopus is correct